Tech120 Domain 40: Advanced Medical Laboratory Practices Quiz

When identifying parasite ova ALWAYS look at the shape of the ova as well as whether or not there is a double membrane.

Monocytes are white blood cells that have a single nucleus and can ingest (take in) foreign material. A monocyte is thus a mononuclear phagocyte that circulates in the blood. Monocytes may also differentiate into cells called macrophages which play an important role in killing of some bacteria protozoa and tumor cells; release substances that stimulate other cells of the immune system; and are involved in antigen presentation.

IgG is the most abundant immunoglobulin and is really important in immunity. Humoral immunity = production of antibody which becomes part of the body fluids (termed 'humors') especially serum. Cell mediated/cellular immunity = process of containing or destroying cells with cell surface foreign antigens.

An immune response is the specific response to a substance that the body does not identify as one of its own. Immune responses can be humoral or cellular and is dependent on the thymus. The thymus converts the stem cells to B and T lymphocytes which then help antibodies to form increase cellular immunity and immunological memory. This is why transplant patients must continue to take medication so their body does not reject the transplant.

The titer testing should be performed 2 to 6 weeks after collection of the first serum sample to accurately measure antibody units per unit volume of serum.

In a Gram Stain Gram negative bacteria stain red or pink and gram positive bacteria stain blue/black/purple.

Many organisms take longer than 24 hours to grow substantially to determine growth. A full 5 days should be given to any agar plated growth prior to reporting it as 'no growth.'

Properly collected and stored samples should be plated as soon as possible. Anaerobic samples should be plated on blood agar (a very good growth medium) as well as in thioglycollate broth (a liquid). Both of these must be contained in an anaerobic environment until testing is completed.

The trophozoite is the Giardial organism released when the Giardia cyst wall is digested away. Giardia is also a protozoan species like Coccidia but has the additional 'trophozoite' stage. Coccidia have all of the following stages: an oocyst a thick-walled structure in which sporozoan zygotes develop and serves to transfer them to new hosts; and a sporozoite is a minute undeveloped sporozoan.

Schizont is the term for asexual development of parasites that form cysts like Coccidia.

Zinc sulfate is used most often because it causes the least amount of distortion making it easier for an effective diagnosis.

Leukopoiesis is the formation of white blood cells. Leukocytosis is an increase in white blood cells in response to disease or infection. Leukocytolysis is the disintegration of leukocytes. Leukopenia is the reduction of the number of leukocytes in the blood.

When analyzing urine is delayed many changes can occur to all of the above but the bacteria overgrowth is most likely to occur first.

Refractometers must be calibrated with distilled deionized water on a regular basis. The little screwdriver in the refractometer box is used to calibrate the instrument. No equipment is maintenance-free. Note: There are specific gravity refractometers available for cats (not labeled as such but used by feline practitioners) due to cats' higher S.G. From Dr. Joyce Knoll and Ms. Cheryl Stockman from Tufts University Clin Path Lab: 'The new veterinary refractometers now go up to 1.080. Dilution is a tricky thing and generally ... hospital labs do not have calibrated pipettes to give accurate dilution factors. It's best to use an accurately calibrated refractometer without dilution.

Calcium oxalate (CaOx) crystals can be found in all urine (two types): dihydrate calcium oxalate crystals in normal urine (envelopes); monohydrate calcium oxalate crystals in urine of animals with ethylene glycol toxicity (long cylindrical shapes with pointed ends). CaOx crystals are common in acid and neutral urine and sometimes alkaline urine. CaOx can be normal in urine if oxalate rich foods (tomatoes, spinach, rhubarb, garlic, oranges, and asparagus) have been eaten or if Vitamin C dosage is high (by-product of ascorbic acid breakdown). Large amounts of CaOx crystals in a freshly voided urine sample may suggest oxalate calculi. Pathologic CaOx presence may mean: ethylene glycol poisoning, diabetes mellitus, liver disease, and severe chronic renal disease.

Casts are formed in the renal tubules the loop of Henle and collecting ducts of the kidneys. Their primary component is the Tamm-Horsfall mucoprotein that is secreted by tubular epithelial cells. If you see casts the pathology is NOT in the ureter bladder or urethra but their presence implies that the disease is still active or ongoing and is in the kidneys.

Although basophils and mast cells have similar functions and enzymatic contents, basophils do not become mast cells. The key word in the question is 'resemble'. If you misread this question, read it again a little slower and think about what it is asking for specifically first.

Even though all can be used sodium citrate is the first choice. Blood for coagulation testing should be collected into a blue top tube containing sodium citrate because the anticoagulant is easily reversed by the addition of ionized calcium. After mixing the sample should be centrifuged for 5 min than plasma should be removed and transferred to a clean tube without anticoagulant. Ethylenediamine tetra-acetic acid (EDTA) is the anticoagulant of choice for a CBC count because it best preserves the cellular components of the blood and prevents platelet aggregation.

K+ is potassium.

New methylene blue is used to detect fat as it gives excellent nuclear detail for better diagnosis. Giemsa and Diff-Quik are used for identifying blood cells, ear cytology, etc. Sudan stains are used to identify fecal fat in samples.

Beta shows complete hemolysis, Alpha shows incomplete hemolysis, Gamma shows no hemolysis. A spore is a form of bacteria that varies in shape, size, and location in the cell.

Cheyletiella is 'walking dandruff' and is easily obtained by adhering tape to the animal's fur. Demodex is located within hair follicles and can be obtained by scraping the skin deep enough to reach the capillaries. Otodectes is the ear mite. Sarcoptes is known as 'human scabies' and can only be obtained through skin scraping.

Lipemia causes visible turbidity of the serum often making it opaque to transmitted light. Lipemia is white or milky on color due to the animal eating before the blood was drawn. Icterus means a liver component and the color would be yellow. Plasma is the liquid portion of the blood.

Toxic neutrophil is usually seen with an underlying disease or bacterial infection. Band cell is an immature cell with an unlobulated band nucleus that may be released into circulation. Metamyelocyte is a precursor in the granulocytic series. Hypersegmented neutrophil is normally seen with several lobes in older animals.

Amorphous urate crystals tend to form in acidic urine and may have a yellow-brown color. Amorphous phosphates are similar in appearance but tend to form in alkaline urine. Generally, they are of no specific clinical value. Calcium oxalate crystals are seen as colorless squares and can appear in urine of any pH. Triple phosphate crystals appear as colorless 'coffin lids' and form in neutral to alkaline urine. Uric acid crystals may appear as yellow to brown or hexagonal plates or needles.

Bacillus and Clostridium are the two gram-positive spore forming rods. The difference between the two is that bacillus is aerophobic while clostridium is aerophilic. Both work by releasing various exotoxins. E-coli and pseudomonas are both gram negative rods. Pasteurella is gram negative cocci and Campylobacter is a gram negative rod. Staphylococcus and Streptococcus are both gram positive cocci.

Spherocytes are almost spherical in shape. They are darkly staining erythrocytes that lack central pallor. They appear to be small but their volume is normal. Spherocytes are not easily detected in species other than dogs because of the small size and lack of central pallor. They are not biconcave like a normal red blood cell and are often seen with hemolytic anemia. Echinocytes are also called 'crenated cells' and appear to have numerous fine uniform spicules throughout. Acanthocytes are also known as 'spur cells' and appear as finger-like projections and have a decreased survival time; may be seen with liver abnormalities. Target cells appear as a target with a bull's-eye; seen in liver disease and iron deficiency.

Normal range for a dog is 37-55% and normal range for a cat is 30-45%. 27% is too low and 60% is considered too high. The 30-45% range only covers the cat. A dog with a PCV of 30% would be considered too low. A PCV of 45-60% would not be considered a normal range for either the dog or cat.