Blood Tests Revision
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A 68 year old gentleman is brought into MAU severely unwell. He is pyrexial and shocked. His wife reports he had been complaining of feeling breathless and a cough over the last few days. His only medical history is that he is on Lisinopril for his blood pressure and has been taking Brufen for osteoarthritis in his knees. On examination he is pyrexial (Temp 38.1oC) with a heart rate of 120bpm and a systolic blood pressure of 90mmHg. He is breathless and examination of his chest shows reduced air entry and bronchial breathing at the right base. A chest x-ray shows right lower zone consolidation. Blood tests and blood cultures are taken and he is catheterised and treated with IV fluids and empirical antibiotics. The first blood tests to come back show: (normal ranges are in brackets) WBC 19.1 x 109/L (4-11) Hb 13 g/dL (Men 13-18, Women 12.1-15.1) Platelets 460 x 109/L (150-450) Na+ 148 mmol/l (135-145) K+ 6.6 mmol/l (3.5-5.0) Urea 37 mmol/l 2(2.5-7.0) creatinine 552 micromol/l (55-110) Which of the following statements are false?
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This gentleman has sepsis
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This gentleman has acute kidney injury
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The most worrying blood result is the creatinine of 552 micromol/l
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His presentation is due to right sided pneumonia
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About This Quiz
Test your knowledge of common blood tests used in medicine
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- 2.
An overweight 54 year old woman attends her GP surgery complaining of lethargy and increased thirst. Her GP performs some blood tests which show a random glucose of 13.2. (4.0-7.8) Which of the following statements is true
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A diagnosis of diabetes mellitus can be made
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A fasting glucose test is required, and if this is greater than 7.1 mmol/l, a diagnosis of diabetes can be made
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This patient probably has Type 1 diabetes mellitus
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This lady probably has type 2 diabetes mellitus and should have an oral glucose tolerance test to confirm the diagnosis
Correct Answer
A. A diagnosis of diabetes mellitus can be madeExplanation
Methods and criteria for diagnosing diabetes mellitus
1. Diabetes symptoms (ie polyuria, polydipsia and unexplained weight loss) plus
a random venous plasma glucose concentration › 11.1 mmol/l
or
a fasting plasma glucose concentration › 7.0 mmol/l (whole blood › 6.1mmol/l)
or
two hour plasma glucose concentration › 11.1 mmol/l two hours after 75g anhydrous glucose in an oral glucose tolerance test (OGTT).
2. With no symptoms diagnosis should not be based on a single glucose determination but requires confirmatory plasma venous determination. At least one additional glucose test result on another day with a value in the diabetic range is essential, either fasting, from a random sample or from the two hour post glucose load. If the fasting or random values are not diagnostic the two hour value should be used
From diabetes.org.ukRate this question:
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- 3.
A 19 year old woman is brought in to A&E following a collapse. On examination she is alert, but complaining of feeling weak, tired and has vague abdominal pain. On examination she is hypotensive and her skin looks tanned. Her capillary blood glucose is 3.1. Her mother, who is with her, states that she has no significant medical history and is on no regular medication, but had recently been complaining of feeling lightheaded and losing weight, and had missed a lot of her university course. Her U&Es show: Na+ 122 mmol/l (135-145) K+ 5.8 mmol/l (3.5-5.0) Urea 6.0 mmol/l (2.5-7.0) Creatinine 91 micromol/l (55-110) What is the likely diagnosis?
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Type 1 diabetes mellitus
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Insulin overdose
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Anorexia nervosa
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Hyperthyroidism
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Addison's disease
Correct Answer
A. Addison's diseaseExplanation
The likely diagnosis in this case is Addison's disease. The patient presents with symptoms of weakness, tiredness, abdominal pain, and hypotension. Her skin appears tanned, which can be a sign of hyperpigmentation in Addison's disease. The electrolyte abnormalities, including hyponatremia and hyperkalemia, are consistent with adrenal insufficiency. Additionally, the patient's recent weight loss and lightheadedness can be attributed to the adrenal gland's inability to produce sufficient cortisol and aldosterone.Rate this question:
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- 4.
Continuing from the previous case, the admitting doctor decides to perform a short synacthen test to confirm the diagnosis. Baseline cortisol = 160 mmol/l (>170) 30 minute sample = 320 mmol/l (>580) True or False? The above tests suggest hypopituitarism.
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True
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False
Correct Answer
A. FalseExplanation
The diagnosis in this case is Addison's disease. The clues in the presentation are the symptoms of weight loss, pre-syncope/syncope and lethargy, the tanned appearance and the biochemical picture (with low sodium and high potassium). The synacthen test shows a low baseline cortisol and an inadequate response to synacthen, suggesting the problem is in the adrenal glands themselves rather than the pituitary.Rate this question:
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- 5.
A 71 year old lady presents to her GP with tiredness and breathlessness on exertion. Her FBC shows Hb 7.2 g/dL (12.1-15.1) MCV 73 fL (82-98) WBC 8.3 x109 (4-11) Platelets 336 x109 (150-450) What is the most likely cause for this haematological picture?
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B12 deficiency
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Folate deficiency
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Myelodysplasia
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Iron deficiency
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Anaemia of chronic disease
Correct Answer
A. Iron deficiencyExplanation
Anaemia with a low MCV is most likely due to iron deficiency. It would be important to ask about symptoms of weight loss, change in bowel habit and any evidence of PR bleeding as there is a strong index of suspicion for bowel malignancy in a patient presenting like this.Rate this question:
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- 6.
A 39 year old gentleman presents to A&E complaining of feeling unwell and abdominal swelling. He is well known to the A&E staff having frequently presented with problems related to alcohol excess. He admits to drinking over 120 units a week. On examination he is jaundiced and has signs of liver failure and ascites. What would you expect his blood tests to show?
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High albumin, high bilirubin, high liver enzymes, high MCV, high PT
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Normal albumin, high bilirubin, high liver enzymes, normal MCV, normal PT
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Low albumin, high bilirubin, high liver enzymes, high MCV, high PT
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Low albumin, high bilirubin, high liver enzymes, high MCV, normal PT
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High albumin, high bilirubin, high liver enzymes, low MCV, low PT
Correct Answer
A. Low albumin, high bilirubin, high liver enzymes, high MCV, high PTExplanation
This gentleman has alcoholic liver disease. His liver enzymes (ALT/AST/GGT) will be raised and as he is jaundiced you would clearly expect his bilirubin to also be raised. His liver's synthetic function will be impaired, which would result in reduced production of albumin and clotting factors (leading to a prolonged prothrombin time). A macrocytosis (raised MCV) would also be expected.Rate this question:
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- 7.
Interpret these thyroid function tests: TSH 0.02 (0.35-5.5 miu/L) Free T4 29 (9-18 pmol/L) Free T3 18 (3.1-7.7 pmol/L)
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Hypothyroidism
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Hyperthyroidism
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Hypopituitarism
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Pituitary tumour
Correct Answer
A. HyperthyroidismExplanation
The given thyroid function test results show a low TSH level (0.02 miu/L) and high levels of Free T4 (29 pmol/L) and Free T3 (18 pmol/L). This pattern is consistent with hyperthyroidism, a condition where the thyroid gland produces an excessive amount of thyroid hormones. In hyperthyroidism, the low TSH level indicates that the pituitary gland is not producing enough TSH to stimulate the thyroid gland. The high levels of Free T4 and Free T3 indicate an overactive thyroid gland. This combination of results is characteristic of hyperthyroidism.Rate this question:
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- 8.
Interpret these thyroid function tests: TSH 0.02 (0.35-5.5 miu/L) Free T4 7 (9-18 pmol/L) Free T3 1.2 (3.1-7.7 pmol/L)
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Hypothyroidism
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Hyperthyroidism
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Hypopituitarism
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Pituitary tumour
Correct Answer
A. HypopituitarismExplanation
The TSH level is very low (0.02) which suggests that the pituitary gland is not producing enough thyroid-stimulating hormone. This can be a sign of hypopituitarism, a condition where the pituitary gland does not produce enough hormones. The low TSH level also leads to low levels of Free T4 (7) and Free T3 (1.2), indicating an underactive thyroid. This pattern of thyroid function tests is consistent with hypopituitarism rather than hypothyroidism or hyperthyroidism. Pituitary tumor can also cause hypopituitarism by affecting the production of TSH.Rate this question:
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- 9.
Interpret these thyroid function tests: TSH 12.2 (0.35-5.5 miu/L) Free T4 6 (9-18 pmol/L) Free T3 1.3 (3.1-7.7 pmol/L)
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Hypothyroidism
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Hyperthyroidism
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Hypopituitarism
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Pituitary tumour
Correct Answer
A. HypothyroidismExplanation
When looking at thyroid function tests it is important to remember the hormone feedback loop (the hypothalamus-pituitary-thyroid axis). TSH is released from the pituitary to stimulate the thyroid gland to release thyroid hormones (T3 and T4). The T3 & T4 levels in turn then tell the pituitary (and hypothalamus) whether increased or decreased thyroid hormone production is required.
In hypothyroidism, the thyroid gland is underactive so T3 & T4 levels would be low. This in turn would tell the piruitary (and hypothalamus) that increased production of thyroid hormones is required, so TSH levels would be high.
In hyperthyroidism, the reverse is true; the thyroid gland is overactive, so T3 & T4 levels are high, in turn telling the pituitary (and hypothalamus) that reduced production of thyroid hormones is required, so TSH would be low.
In hypopituitarism, the problem is in the pituitary gland. It is not secreting enough TSH so the thyroid gland is not getting the message to produce thyroid hormones. Therefore, both TSH and T3/T4 would be low.Rate this question:
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Mar 22, 2023Quiz Edited by
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Aug 19, 2011Quiz Created by
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