Urinalysis Study Questions

The presence of RBC casts in the urinary sediment indicates bleeding within the nephron. RBC casts are formed when red blood cells aggregate and become trapped in the renal tubules. This suggests that there is active bleeding within the kidney, as the red blood cells are being filtered out of the blood and into the urine. The other options, such as RBCs alone, WBC casts, and hyaline casts, may also be present in various kidney conditions, but RBC casts specifically indicate bleeding within the nephron.

The kidney plays a crucial role in maintaining the acid-base equilibrium, eliminating waste products of metabolism, and getting rid of foreign substances from the body. However, the primary function of the kidney is not to rid the body of excess protein. While the kidney does filter and excrete small amounts of protein, its main function regarding protein is to reabsorb it and prevent its loss in the urine. Therefore, the correct answer is to rid the body of excess protein.

Crenation of red cells in the urine indicates that the urine is hypertonic. This means that the concentration of solutes in the urine is higher than that of the red blood cells. In a hypertonic solution, water tends to move out of the cells, causing them to shrink and develop a crenated or wrinkled appearance. Therefore, the presence of crenated red cells suggests that the urine has a higher solute concentration, making it hypertonic.

Tuberculosis is not frequently associated with joint disorders. While tuberculosis can affect the bones and joints, it is not a common manifestation of the disease. Joint involvement in tuberculosis is known as tuberculous arthritis, and it occurs in a small percentage of cases. In contrast, Lyme disease, lupus erythematosus, and rheumatoid arthritis are all known to frequently cause joint disorders.

The stools of a bleeding ulcer (duodenal) patient will appear black. This is because when there is bleeding in the upper gastrointestinal tract, the blood gets partially digested by stomach acid, resulting in a black, tarry appearance of the stool called melena. This occurs due to the presence of iron in the blood. It is important to note that black stools can also be caused by other conditions such as gastrointestinal bleeding from other sources or the consumption of certain medications or foods.

Phenylketonuria is caused by the absence of phenylalanine hydroxylase. This enzyme is responsible for converting the amino acid phenylalanine into another amino acid called tyrosine. Without phenylalanine hydroxylase, phenylalanine builds up in the body and can cause various health problems.

Dilute acetic acid should be added to remove the precipitate of RBCs in urine. Acetic acid is a weak acid that helps to dissolve the sediment and clear the urine. It is commonly used in urine analysis to improve visibility and allow for accurate examination of the remaining sediment. Sodium hydroxide, ammonium hydroxide, and nitric acid are not suitable for this purpose and may cause further complications or interfere with the analysis.

During urine formation, plasma proteins are generally not allowed to filter through the glomerular capillaries. This is because the glomerular capillaries have small pores that only allow small molecules like water, ions, and waste products to pass through. Plasma proteins are large molecules that are important for maintaining osmotic pressure and other functions in the blood, so they are usually retained in the bloodstream and not filtered into the urine.

Urea is the correct answer because it is the main component of urinary dissolved organic solids. Urea is a waste product formed in the liver when proteins are broken down. It is then filtered out of the blood by the kidneys and excreted in urine. Protein, creatinine, and sodium are also present in urine, but they do not make up the majority of urinary dissolved organic solids.

Amorphous phosphates are usually white in color when observed macroscopically. This means that when looking at a larger scale, such as with the naked eye or a microscope, the phosphates appear white. This is a characteristic color for amorphous phosphates and can help in their identification and differentiation from other substances.

Pyelonephritis is the disorder associated with the presence of WBC casts in a urine sediment. Pyelonephritis is a bacterial infection of the kidneys, typically caused by a urinary tract infection that has spread from the bladder. The presence of WBC casts in the urine sediment indicates inflammation and infection in the renal tubules, which is a characteristic feature of pyelonephritis. Glomerulonephritis is associated with the presence of RBC casts, nephrotic syndrome is associated with proteinuria and edema, and tubular necrosis is associated with the presence of renal tubular epithelial cell casts.

A spotted reaction on the reagent strip for blood indicates hematuria. Hematuria refers to the presence of red blood cells in the urine, which can be caused by various conditions such as urinary tract infections, kidney stones, or bladder cancer. The reagent strip detects the presence of blood by reacting with the heme component of hemoglobin, the oxygen-carrying protein in red blood cells. Therefore, a positive reaction on the reagent strip indicates the presence of blood in the urine, suggesting hematuria.

Ehrlich's aldehyde reagent is used in the determination of urobilinogen. Urobilinogen is a colorless compound that is formed in the intestines by the reduction of bilirubin. It is then absorbed into the bloodstream and excreted in the urine. Ehrlich's aldehyde reagent reacts with urobilinogen to form a pink to red color, allowing for its detection and measurement. This test is commonly used in the diagnosis of liver diseases and disorders that affect the breakdown and excretion of bilirubin.

Carbonate crystals are more commonly found in alkaline urine. This is because alkaline urine has a higher pH, which promotes the formation of certain types of crystals, including carbonate crystals. On the other hand, acid urine, which has a lower pH, is less likely to support the formation of carbonate crystals. Therefore, alkaline urine is the more favorable environment for the presence of carbonate crystals.

Casts are cylindrical structures that are formed in the renal tubules and are typically composed of cellular debris or protein. They are not normally present in the urine, but their presence can indicate various kidney disorders. The other options, RBCs, WBCs, and bacteria, are all commonly reported as the quantity per high power field in a urine analysis, indicating the presence of red blood cells, white blood cells, and bacteria in the urine, respectively.

Ammonia is not an organic substance found in urine. Organic substances are compounds that contain carbon atoms bonded to hydrogen atoms. Urea, uric acid, and creatinine are all organic substances that are normally present in urine. Ammonia, on the other hand, is a compound that does not contain carbon-hydrogen bonds and is typically excreted in the form of ammonium ions rather than as ammonia gas in urine.

Calcium oxalate is the most common chemical constituent found in renal or bladder stones. Renal or bladder stones are formed when certain substances in the urine, such as calcium and oxalate, become highly concentrated and crystallize. Calcium oxalate stones can form due to various factors, including a diet high in oxalate-rich foods, low fluid intake, and certain medical conditions. These stones can cause symptoms such as severe pain, blood in the urine, and frequent urination. Treatment options may include medication, dietary changes, and in some cases, surgical intervention.

The normal CSF protein level is measured in milligrams per deciliter (mg/dL). The range of 15 to 45 mg/dL is considered normal. This means that the concentration of protein in the cerebrospinal fluid falls within this range in a healthy individual. Protein levels outside of this range may indicate certain medical conditions or abnormalities in the central nervous system.

Quantitation of a substance that varies with daily activities should be performed on a 24-hour specimen. This is because a 24-hour specimen provides a more comprehensive and accurate representation of the substance's levels throughout the entire day, capturing any fluctuations that may occur due to daily activities. Other specimens, such as random or first morning specimens, may only capture a snapshot of the substance's levels at a specific time, which may not be representative of its overall variation. A 2-hour postprandial specimen, on the other hand, is specifically used to measure the substance's levels after a meal and may not provide a complete picture of its daily variation.

Ketones are unstable compounds that can degrade over time, especially when exposed to room temperature. Prolonged sitting of a urine sample at room temperature can lead to the breakdown of ketones, resulting in a decrease in their concentration. Therefore, the correct answer is decreased.

During attacks of gout, crystals found in synovial fluid are monosodium urate. Gout is a form of arthritis that occurs when there is a buildup of uric acid in the blood, leading to the formation of urate crystals in the joints. These crystals can cause severe pain, inflammation, and swelling. Therefore, the presence of monosodium urate crystals in synovial fluid confirms the diagnosis of gout. Calcium pyrophosphate crystals, cholesterol, and apatite are not typically associated with gout.

Porphyrins are intermediary compounds in the formation of heme. Heme is an important molecule involved in various biological processes, including oxygen transport and energy production. Porphyrins are synthesized in the body and undergo a series of chemical reactions to eventually form heme. Heme is then incorporated into proteins such as hemoglobin and myoglobin, which are crucial for the transport and storage of oxygen in the body. Therefore, heme is the correct answer as it represents the final product of the formation of porphyrins.

Leukocytes in urine are typically larger than renal epithelial cells, contain nuclei, and are not dissolved by acetic acid. Therefore, the characteristic that is not associated with leukocytes in urine is being larger than erythrocytes.

The correct answer is 1200 mL/min. This is because the kidneys receive a large amount of blood flow in order to filter waste products and maintain fluid balance in the body. The kidneys receive about 20% of the total cardiac output, which is approximately 6000 mL/min. Therefore, the total renal blood flow is estimated to be around 1200 mL/min.

Multistix may become unreliable if they are allowed to absorb moisture. This is because the presence of moisture can cause the reagents on the Multistix to degrade or react prematurely, leading to inaccurate results. It is important to store Multistix in a dry environment and use them promptly to ensure their reliability.

An ADH deficiency impairs the ability of the kidneys to concentrate urine, resulting in the excretion of a larger volume of more dilute urine. This leads to a low specific gravity, as the urine is less concentrated and contains a higher proportion of water.

A urine specimen with a pH of 9.0 indicates that the patient should be asked to collect a new specimen. This is because a pH of 9.0 is highly alkaline and outside the normal range for urine pH, which is typically between 4.6 and 8.0. It is possible that there was an error in the collection or testing process, leading to an inaccurate result. Collecting a new specimen will help ensure a more accurate assessment of the patient's urinary pH.

Leaving a Multistix test strip in contact with urine for too long can cause leaching of reagents. This means that the chemical substances in the test strip, which are responsible for producing a reaction and indicating the presence or absence of certain substances in the urine, may dissolve and spread into the surrounding urine. As a result, the accuracy and reliability of the test may be compromised, leading to incorrect or inconclusive results.

The concentration of urine mostly takes place in the distal convoluted tubules and the collecting duct of the kidney. These structures are responsible for reabsorbing water and solutes from the filtrate, thereby concentrating the urine. The loop of Henle is primarily involved in establishing a concentration gradient, while the glomeruli and Bowman's capsules are responsible for the initial filtration of blood. The proximal convoluted tubules also play a role in reabsorption, but not as significant as the distal convoluted tubules and collecting duct in concentrating urine.

Urinary stasis refers to the condition where urine remains stagnant or does not flow properly. This can occur due to various reasons such as urinary tract obstruction or impaired bladder emptying. Urinary stasis creates an ideal environment for the formation of casts, which are cylindrical structures composed of protein and cellular debris. When urine stagnates, the concentration of these substances increases, leading to their precipitation and subsequent formation of casts. Therefore, urinary stasis is the primary factor that favors the formation of casts.

Inadequate hydration can lead to the formation of crystals due to medications. When the body is not properly hydrated, the concentration of the medication in the urine increases, making it more likely for crystals to form. Adequate hydration helps to dilute the medication and prevent the formation of crystals. Therefore, inadequate hydration is the most common cause of crystal formation in relation to medications.

The correct answer is "lysis of yeast cells by acetic acid". This is because acetic acid does not cause lysis or destruction of yeast cells. Lysis refers to the breaking down or disintegration of cells, which can be caused by various factors such as chemicals or enzymes. However, yeast cells are not affected by acetic acid in this way. Therefore, using acetic acid to induce lysis would not be an effective method for differentiating among RBCs, yeast, and oil droplets.

Ketone bodies occur when there is an abnormal oxidation of fatty acids. During this process, fatty acids are broken down to produce energy, and ketone bodies are formed as byproducts. This can happen when the body is not able to effectively use glucose for energy, such as in conditions like diabetes or during prolonged fasting. The presence of ketone bodies in the blood can indicate a state of ketosis, which can have various implications for health and metabolism.

Cystitis is the correct answer because it refers to the infection of the bladder. The term "cyst" in cystitis refers to the bladder, and the suffix "-itis" indicates inflammation or infection. Pyelitis refers to the infection of the renal pelvis, nephritis refers to the inflammation of the kidneys, and bacteriuria refers to the presence of bacteria in the urine.

Diabetic patients are tested for microalbuminuria to detect the presence of early renal disease. Microalbuminuria refers to the presence of small amounts of albumin (a protein) in the urine. This is an important marker for kidney damage in diabetic patients, as it indicates the early stages of diabetic nephropathy. Regular screening for microalbuminuria allows for early detection and intervention to prevent further kidney damage and complications.

Osmolarity is a measure of the concentration of solute particles in a solution, regardless of their size or type. It takes into account all solute molecules, both small and large, and provides a more comprehensive assessment of the renal concentrating ability. Specific gravity, on the other hand, is influenced by the presence of certain solute molecules such as urea and glucose, but it does not consider the concentration of other solute particles. Therefore, osmolarity is a more accurate measure of renal concentrating ability as it considers all solute particles equally.

The most probable cause of a white precipitate that is macroscopically visible in urine is amorphous phosphates. Amorphous phosphates are a type of crystal that can form in urine when there is an excess of phosphate ions. This can occur due to a variety of reasons, such as a high protein diet or urinary tract infections. When these crystals precipitate out of the urine, they can appear as a white sediment. Lipids and radiographic contrast media are not typically present in urine in sufficient quantities to cause visible precipitates, and amorphous urates would appear as a reddish-brown sediment rather than white.

The liver is the correct answer because it is the main organ responsible for urea formation. Urea is a waste product that is formed in the liver during the breakdown of proteins. The liver plays a crucial role in metabolism and detoxification, and one of its functions is to convert ammonia, a toxic byproduct of protein metabolism, into urea. Urea is then transported to the kidneys for excretion in the urine. The spleen, kidney, and bladder do not have a significant role in urea formation.

The presence of RBC casts in a urine sediment is indicative of glomerulonephritis. Glomerulonephritis is a condition characterized by inflammation of the glomeruli, which are the tiny blood vessels in the kidneys responsible for filtering waste and excess fluid from the blood. This inflammation can cause damage to the glomeruli, leading to the presence of RBC casts in the urine. Other symptoms of glomerulonephritis may include blood in the urine, proteinuria, high blood pressure, and decreased urine output.

Protein is the correct answer because it is the most stable out of the options listed. When a specimen is left at room temperature overnight, bilirubin and urobilinogen can degrade, leading to changes in their levels. RBCs can also lyse and break down, causing changes in their appearance and count. However, proteins are generally more resistant to degradation and can remain relatively stable even when left unpreserved for a short period of time.

A 1% concentration of urinary protein would increase the specific gravity of urine by 0.003. This means that for every 1% increase in the concentration of urinary protein, the specific gravity of urine would increase by 0.003.

Bence Jones protein is a type of protein that is found in the urine of individuals with multiple myeloma, a type of cancer. It is characterized by its unique property of being soluble at boiling temperature. Unlike other urinary proteins, Bence Jones protein remains dissolved in urine even when heated, which allows for its detection through laboratory tests. This solubility at boiling temperature is a distinguishing feature of Bence Jones protein and helps in its identification and diagnosis.

Stored urine sediment is typically associated with the presence of various components such as casts, red cells, and white cells. However, amorphous deposits and crystals are not typically found in stored urine sediment. These substances are more commonly observed in freshly collected urine samples due to their solubility and tendency to dissolve over time. Therefore, the absence or loss of amorphous deposits and crystals in stored urine sediment is expected.

Trichomonas vaginalis is a parasite that causes trichomoniasis, a sexually transmitted infection. During a urine sediment examination, the motility of Trichomonas vaginalis would be most noticeable. This is because Trichomonas vaginalis is a flagellated organism, meaning it has whip-like structures called flagella that allow it to move. The movement of Trichomonas vaginalis can be easily observed under a microscope, making it the most noticeable motility during a urine sediment examination.

Casts are precipitates of protein that are formed mostly in the distal convoluted tubule. This part of the nephron is responsible for reabsorbing water and electrolytes from the filtrate, and any excess proteins that are not reabsorbed can form casts in this region. Casts can indicate various kidney diseases or conditions, such as glomerulonephritis or tubular damage. Therefore, the presence of casts in the urine can be a sign of underlying kidney problems.

The creatinine clearance is calculated by dividing the urine creatinine concentration by the serum creatinine concentration and multiplying by the urine volume over time. In this case, the urine creatinine concentration is 120 mg/dL, the serum creatinine concentration is 1.5 mg/dL, and the urine volume is 720 mL for 12 hours (which is equivalent to 60 mL/hour).

Creatinine clearance = (Urine creatinine concentration / Serum creatinine concentration) x Urine volume over time
Creatinine clearance = (120 mg/dL / 1.5 mg/dL) x 60 mL/hour
Creatinine clearance = 80 ml/min

Therefore, the correct answer is 80 ml/min.

Crenated RBCs are red blood cells that have shriveled and developed abnormal, spiky shapes due to dehydration or exposure to hypertonic solutions. A specific gravity of 1.038 indicates a highly concentrated urine, which means there is a higher concentration of solutes in the urine compared to pure water. This concentration can cause dehydration and lead to the crenation of red blood cells. Therefore, crenated RBCs are most likely to be found in a urine sample with a specific gravity of 1.038.

Ghost RBCs are red blood cells that have lost their hemoglobin content, leaving behind a pale, transparent appearance. Dilute alkaline urine can cause the hemoglobin to be washed out of the RBCs, resulting in the formation of ghost RBCs. Therefore, when examining dilute alkaline urine, it is important to carefully look for the presence of ghost RBCs.

Increased maternal serum alpha fetoprotein (MSAFP) is a marker for fetal neural tube disorders such as spina bifida and anencephaly. MSAFP is a protein produced by the fetus and normally found in the amniotic fluid and maternal serum. However, when there is a defect in the neural tube, such as an incomplete closure, MSAFP leaks into the amniotic fluid and then into the maternal bloodstream. Therefore, an increased level of MSAFP in the maternal serum suggests the presence of a fetal neural tube disorder.

Stools from persons with steatorrhea contain excess amounts of fat. Steatorrhea is a condition characterized by the presence of excessive fat in the stool, indicating malabsorption of dietary fats. This can be caused by various factors such as pancreatic insufficiency, celiac disease, or liver disease. The excess fat in the stool gives it a greasy appearance and is often accompanied by foul-smelling stools and weight loss.

The result that should be repeated is pH 7.5 with uric acid crystals. This is because an abnormal pH level combined with the presence of uric acid crystals may indicate a potential kidney or urinary tract issue. Repeating the test can help confirm the accuracy of the initial result and provide further information for diagnosis and treatment.

The uneven distribution of blood among the three tubes and the presence of clots in a CSF specimen indicate a traumatic tap. A traumatic tap occurs when there is an accidental injury to a blood vessel during the collection of cerebrospinal fluid. This can lead to blood mixing with the CSF, resulting in an uneven distribution and the formation of clots. Other conditions like meningitis, cerebral hemorrhage, and multiple sclerosis may have different indications in a CSF specimen, making traumatic tap the most likely explanation based on the given information.

Gardenerella vaginalis is the correct answer because it is a bacterium commonly associated with bacterial vaginosis, a condition characterized by an overgrowth of bacteria in the vagina. Clue cells are vaginal epithelial cells that are covered with bacteria, and the presence of Gardenerella vaginalis on these cells is indicative of bacterial vaginosis. Trichomonas vaginalis is a protozoan parasite that causes trichomoniasis, not bacterial vaginosis. Escherichia coli is a common bacterium found in the intestines and is not typically associated with clue cells. Candida albicans is a yeast that can cause vaginal yeast infections, but it is not typically associated with clue cells or bacterial vaginosis.

Fatty casts are the only type of cast capable of polarization. Polarization is a technique used to identify the presence of certain substances in a sample. Fatty casts are formed when there is lipid accumulation in the renal tubules, which can be seen under polarized light due to their birefringent properties. Hyaline casts are composed of protein and do not polarize. Waxy casts are formed in the presence of severe renal disease and do not polarize either. Granular casts are made up of cellular debris and do not exhibit polarization. Therefore, the correct answer is fatty cast.

The serous fluid serves as a lubricant for the serous membranes. These membranes line the body cavities and organs, reducing friction between them and allowing for smooth movement. The fluid's lubricating properties enable the organs to glide against each other without causing damage or discomfort. It also helps to prevent friction-related inflammation and irritation within the body cavities.

Solid, undissolved particles in urine are better preserved in acid urine because acidic conditions help to prevent the breakdown or dissolution of these particles. Acidic urine creates an environment that is less favorable for the degradation or solubility of these particles, allowing them to remain intact and visible. In contrast, neutral or alkaline urine may promote the dissolution or degradation of these particles, making them less visible or causing them to dissolve completely. Therefore, acid urine is more effective in preserving the solid particles in urine.

Myelin basic protein is measured in the CSF to assess the condition of patients with multiple sclerosis. Multiple sclerosis is a chronic autoimmune disease that affects the central nervous system, causing inflammation and damage to the myelin sheath, which is the protective covering of nerve fibers. Measurement of myelin basic protein levels in the CSF can help in diagnosing and monitoring the progression of multiple sclerosis, as elevated levels indicate ongoing damage to the myelin sheath. This test is not specific to other conditions such as cerebral hemorrhage, bacterial meningitis, or neurosyphilis.

Creatinine is not absorbed in significant amounts during the flow of filtrate through the tubules.

Amniotic fluid serves as a protective cushion for the fetus, shielding it from external pressure and impact. It acts as a shock absorber, preventing any potential harm to the developing fetus during movement or trauma. Additionally, the fluid helps maintain a stable temperature around the fetus, protecting it from temperature fluctuations. It also serves as a barrier against infections, preventing harmful bacteria or viruses from reaching the fetus. Overall, the primary function of amniotic fluid is to provide protection for the fetus throughout its development.

The correct answer is hematology #3, chemistry #1, and microbiology #2 because according to the given distribution, tube #3 should be assigned to hematology, tube #1 should be assigned to chemistry, and tube #2 should be assigned to microbiology.

The presence of WBC casts is a key differentiating factor between cystitis and pyelonephritis. WBC casts are indicative of inflammation in the kidneys, which is a characteristic of pyelonephritis. In cystitis, the inflammation is limited to the bladder and does not typically involve the kidneys. Therefore, the presence of WBC casts suggests pyelonephritis rather than cystitis. The other options, such as performing a cystoscopy, performing blood cultures, and the presence of bacteriuria, may be helpful in diagnosing urinary tract infections but are not specific to differentiating between cystitis and pyelonephritis.

The refractometer reading of 1.003 with distilled water indicates that the instrument is not calibrated correctly. To ensure accurate results, the technologist should adjust the set screw on the refractometer to correct the calibration.

The CSF (cerebrospinal fluid) circulates through the brain and spinal cord in the subarachnoid space. The subarachnoid space is a narrow space between the arachnoid mater and the pia mater, two of the protective layers surrounding the brain and spinal cord. This space is filled with CSF, which acts as a cushion, providing support and protection to the brain and spinal cord. It also helps to remove waste products and deliver nutrients to the nervous tissue.

Persons diagnosed with PKU should avoid food containing aspartame because it contains phenylalanine, an amino acid that individuals with PKU cannot metabolize properly. PKU is a genetic disorder that affects the body's ability to break down phenylalanine, leading to a buildup of this amino acid in the blood. Aspartame is an artificial sweetener commonly found in diet sodas, sugar-free gum, and other low-calorie products. Consuming aspartame can increase the levels of phenylalanine in the body, which can be harmful to individuals with PKU. Therefore, it is important for them to avoid foods and beverages that contain aspartame.

Lipids are substances that are more easily identified using polarized light in the urinary sediment. When polarized light is passed through a sample containing lipids, it causes the lipids to exhibit characteristic birefringence, which allows for their identification. On the other hand, WBCs, casts, and ketone bodies do not exhibit this birefringence and cannot be easily identified using polarized light.

The correct answer is renal tubular, transitional, squamous. This order is based on the location of epithelial cells in the urinary tract. The renal tubular epithelial cells are found in the renal tubules, which are part of the kidney. Transitional epithelial cells are found in the transitional epithelium lining the bladder and ureters. Squamous epithelial cells are found in the urethra and the outermost layer of the bladder. Therefore, the correct order is renal tubular, transitional, squamous.

The presence of a non-glucose reducing substance could explain how the same specimen could give a positive clinitest result and a negative reagent strip result. This means that even though the clinitest detected the presence of a reducing substance, it is not glucose. The reagent strip, on the other hand, did not detect any glucose in the specimen. Therefore, the presence of a non-glucose reducing substance can explain this discrepancy between the two tests.

When specimens contain mucus, they may be mistakenly reported as containing hyaline casts. This is because both mucus and hyaline casts can appear similar under microscopic examination. Hyaline casts are formed from proteinaceous material and can be found in the urine, while mucus is a gel-like substance produced by various body tissues. Therefore, the presence of mucus in a specimen can lead to a misinterpretation and false identification of hyaline casts.

Cylindroids are urinary structures that resemble hyaline casts. Hyaline casts are transparent, colorless cylinders that are composed of protein and are commonly found in the urine. Cylindroids are similar in appearance to hyaline casts but are smaller and more irregular in shape. They can be seen in various kidney disorders, such as glomerulonephritis, and may indicate damage to the renal tubules.

RBCs produce a cloudy specimen because they are larger in size and have a higher refractive index compared to hemoglobin. This causes light to scatter when it passes through the specimen, resulting in a cloudy appearance. On the other hand, hemoglobin, being a pigment, does not scatter light as much and therefore does not produce a cloudy specimen.

The refractive index compares the speed of light in air with the speed of light in solutions. The refractive index is a measure of how much the speed of light changes when it passes through a medium, and it is defined as the ratio of the speed of light in a vacuum to the speed of light in the medium. Therefore, comparing the speed of light in air with the speed of light in solutions allows us to determine the refractive index of the solution.

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The correct answer is "is absorbed in the convoluted tubules." When testing urine with dipstick methods, the glucose result is normally negative because glucose is absorbed in the convoluted tubules. The glomerulus filters waste products from the blood, including glucose, but normally reabsorbs it back into the bloodstream through the convoluted tubules. Therefore, in a healthy individual, there should be no glucose present in the urine as it has been reabsorbed.

A cloudy, yellow-green synovial fluid with a high number of white blood cells (WBCs), predominantly neutrophils, and decreased glucose levels is indicative of an infection. This suggests that there is a bacterial presence in the synovial fluid, causing an inflammatory response. This classification is known as septic arthritis, which is characterized by joint inflammation due to a bacterial infection.

Phase contrast microscopy is often used in clinical laboratories to increase the probability of detecting urine sediment constituents that have a low refractive index. This technique enhances the contrast and visibility of transparent and low-contrast objects by converting phase differences into brightness differences. By using phase contrast microscopy, the subtle differences in refractive index between the urine sediment constituents and the surrounding medium can be highlighted, making it easier to detect and analyze them.

The renin-angiotensin-aldosterone system is responsible for vasoconstriction of the renal arterioles, reabsorption of sodium, and release of aldosterone. However, it does not play a role in lowering the glomerular blood pressure. In fact, the system is activated in response to low blood pressure or low blood volume in order to increase blood pressure and maintain adequate perfusion to the kidneys.

A urine with a high pH indicates that it is more alkaline or basic. This means that there is a low concentration of hydrogen ions in the urine. Hydrogen ions are responsible for making a solution acidic, so a low concentration of hydrogen ions results in a higher pH. Therefore, the correct answer is "low concentration of hydrogen ions."

In biliary duct obstruction, the bile flow from the liver to the intestines is blocked, leading to the accumulation of bilirubin in the bloodstream. Bilirubin is a pigment that is normally excreted in the bile and gives urine its yellow color. Therefore, in the case of biliary duct obstruction, there will be an increased level of bilirubin in the urine, indicated by the presence of "++" in the reagent strip test for bilirubin. On the other hand, urobilinogen is a product of bilirubin breakdown in the intestines. Since the obstruction prevents bilirubin from reaching the intestines, there will be a decreased level of urobilinogen in the urine, indicated by a low value of 0.1 EU.

Pediatric urine specimens are tested for the presence of glucose, galactose, and lactose using different methods. In this case, the correct answer is "glactose using clinitest." This means that the clinitest method is used to test for the presence of galactose in pediatric urine specimens.

Hemolytic disease of the newborn endangers the fetus by causing anemia. This condition occurs when the mother's antibodies attack the red blood cells of the fetus, leading to their destruction. As a result, the fetus experiences a decrease in the number of healthy red blood cells, leading to anemia. Anemia can be dangerous for the fetus as it affects the delivery of oxygen to the body's tissues and organs, potentially leading to complications and developmental issues.

The production of antidiuretic hormone (ADH) is controlled by the state of body hydration. ADH is released by the hypothalamus and acts on the kidneys to regulate water reabsorption. When the body is dehydrated, ADH levels increase, causing the kidneys to reabsorb more water and produce concentrated urine. On the other hand, when the body is well-hydrated, ADH levels decrease, leading to increased urine production and dilution. Therefore, the state of body hydration plays a crucial role in regulating ADH production and water balance in the body.

The presence of cholesterol crystals is associated with nephrotic syndrome. Nephrotic syndrome is a kidney disorder characterized by high levels of protein in the urine, low levels of protein in the blood, high cholesterol levels, and swelling in the body. Cholesterol can accumulate in the kidneys and form crystals, which can contribute to the development of nephrotic syndrome. These crystals can cause damage to the kidneys and disrupt their normal functioning, leading to the symptoms associated with the syndrome.

Effusion refers to the abnormal buildup of fluid in a body cavity. This can occur due to various reasons such as inflammation, infection, or injury. Unlike an abscess, which is a localized collection of pus, an effusion involves a more generalized accumulation of fluid. Transudate, on the other hand, refers to a specific type of fluid that is formed due to increased pressure within blood vessels. Exudate is a fluid that is rich in proteins and cells and is typically associated with inflammation or infection. Therefore, effusion is the correct term to describe the pathologic accumulation of fluid in a body cavity.

Reagent strip reactions for ketones primarily react with acetoacetic acid. This is because acetoacetic acid is a type of ketone that can be detected using reagent strips. Acetone and beta-hydroxybutyric acid are also ketones, but they may not react as strongly or may not be detected by the specific reagent used in the test. Therefore, the correct answer is acetoacetic acid.

The counting chamber is used to determine the concentration of cells in a given volume of fluid. In this case, the CSF specimen is diluted with acetic acid to make it easier to count the cells. The counting is done in five large squares on both sides of the chamber, and a total of 50 cells are counted. The count is then reported as the number of cells per liter of fluid. In this case, the count is 500 WBCs/L, indicating that there are 500 white blood cells per liter of the CSF specimen.

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Fibers can be distinguished from casts in a microscopic exam of a urine sediment because fibers often polarize light. This means that when light passes through the fibers, it becomes polarized and exhibits specific patterns. On the other hand, casts do not typically polarize light. This difference in the behavior of light allows for the differentiation between fibers and casts in a urine sediment examination.

The icotest is a diagnostic test that measures bilirubin levels. The statement "it is less sensitive than the reagent strip test" is not true because the icotest is actually more sensitive than the reagent strip test. The icotest is designed to detect even low levels of bilirubin, making it a highly sensitive test for diagnosing conditions such as jaundice.

Synovial fluid is produced through the process of ultrafiltration of plasma. Ultrafiltration involves the passage of fluid through a semipermeable membrane, which allows small molecules and ions to pass while retaining larger molecules. In the case of synovial fluid production, plasma is filtered through the synovial membrane, selectively allowing certain components to pass through and form the fluid. This process helps in maintaining the lubrication and nourishment of the joints by providing essential nutrients and removing waste products.

CSF electrophoresis is a diagnostic test used to confirm the presence of multiple sclerosis. In multiple sclerosis, there is an immune response in the central nervous system, leading to increased levels of IgG antibodies in the cerebrospinal fluid (CSF). These increased IgG levels can be detected through electrophoresis. Additionally, oligoclonal bands, which are bands of immunoglobulins, are often seen in the CSF of patients with multiple sclerosis. These bands are not typically seen in serum electrophoresis, which is why the correct answer states that CSF electrophoresis would show increased IgG with oligoclonal bands not seen on serum electrophoresis.

The question asks for the test that is not typically performed on synovial fluid. Synovial fluid analysis is commonly used to diagnose joint-related conditions. Gram stain is performed to detect bacterial infection, WBC count is done to assess inflammation, and differential is used to identify different types of cells in the fluid. However, uric acid test is not typically performed on synovial fluid as it is more commonly used to diagnose gout or kidney stones.

WBC casts are not associated with severe urinary stasis. WBC casts are formed when there is inflammation in the kidneys or urinary tract, indicating an infection or inflammation. On the other hand, granular casts, waxy casts, and broad casts are associated with severe urinary stasis. Granular casts are formed when there is degeneration of renal tubular cells, waxy casts indicate chronic renal disease, and broad casts are seen in severe renal disease or chronic renal failure.

The correct answer is that only a blood sample is needed for the eGFR. This test is used to estimate how well the kidneys are functioning by measuring the level of creatinine in the blood. It does not require a urine sample or take into account the patient's race in the calculation.

The degree to which the kidney concentrates the glomerular filtrate can be determined by measuring urine and serum osmolarity. Osmolarity is a measure of the concentration of solutes in a solution. By comparing the osmolarity of urine and serum, we can determine how much the kidney is able to concentrate the filtrate. If the urine osmolarity is higher than the serum osmolarity, it indicates that the kidney is effectively concentrating the filtrate.

A positive nitrite test suggests the presence of a minimum of 10 to the 4th organisms/ml. This means that there are at least 10,000 organisms per milliliter of the sample. The nitrite test is used to detect the presence of bacteria in urine, specifically those that can convert nitrate to nitrite. The higher the number of organisms/ml, the more likely it is that there is a urinary tract infection. Therefore, a positive nitrite test with a minimum of 10 to the 4th organisms/ml indicates a significant bacterial infection.

The presence of oval fat bodies in a urine sediment is associated with tubular necrosis. Oval fat bodies are altered renal tubular epithelial cells that contain fat droplets. In tubular necrosis, there is damage to the renal tubules, causing the shedding of these altered cells into the urine. This condition can be caused by various factors such as ischemia, toxins, or certain medications. Glomerulonephritis is a different condition characterized by inflammation of the glomeruli in the kidney. Nephrotic syndrome is a kidney disorder characterized by excessive protein loss in the urine. Pyelonephritis is a bacterial infection of the kidneys.

Increased exercise may not directly prevent the formation of renal calculi. Renal calculi, also known as kidney stones, are formed when certain substances in the urine crystallize and form solid masses. Increased hydration helps to dilute the urine and prevent the concentration of these substances. Dietary restrictions can also help by avoiding foods high in oxalate or calcium, which are common components of kidney stones. Adjustment of urine pH can be helpful in preventing certain types of stones. However, exercise alone does not have a direct impact on the formation of kidney stones.

The cerebrospinal fluid performs several important functions in the body, including nutritional enrichment of nervous tissue, removal of metabolic waste products, and protection of neurologic tissue from trauma. However, it does not directly participate in the transmission of neurologic impulses. Impulses are transmitted through the neurons themselves, not through the cerebrospinal fluid.

The recommended centrifugation for preparing the urine sediment is 400 RCF for 5 minutes. RCF stands for Relative Centrifugal Force, which is a measure of the force applied to the sample during centrifugation. This specific combination of speed and time is likely to provide optimal separation of the urine sediment, allowing the heavier particles to settle at the bottom of the tube. This centrifugation protocol is commonly used in laboratories to concentrate and collect the sediment for further analysis, such as microscopic examination.