WMTC - West Midlands Training Course » 2007

Short Answer Questions

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Short Answer Questions

below are links to all the short answer question papers that have been archived.

Exams – Short Answers Spring 2007

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Course Assessment – Spring 2007

Short Answer Questions. Answer all questions. Time allowed 1 hour.

There are 10 marks for each question

1) Parathyroid hormone has a plasma half life of 3 minutes. A patient undergoing a parathyroidectomy had an initial plasma value of 137 ng/L. What was the level 11 minutes after isolation of the gland? How long until the PTH level was undetectable? (Limit of detection = 5ng/L)

(5 marks each part)

2) The following results were obtained on venous plasma glucose samples (mmol/L) during an oGTT

Fasting 2 hour Symptoms

Case 1 6.5 12.2 None

Case 2 6.6 7.8 None

Case 3 6.0 7.6 None

Case 4 6.9 15.0 Polyuria/Polydipsia

Case 5 6.1 7.7 None

Interpret the results in the light of the WHO criteria.

( 2 marks each)

3) Define hypoglycaemia. List 8 possible causes of hypoglycaemia in adults

(2 marks & 8 marks)

4) Assuming the salt XCl₂is completely dissociated in water and a 19g/L solution gave an osmolality of 600 mosmol/kg estimate the molecular weight of XCl₂

(10 marks)

5) What volume of a stock glucose solution containing 9.01 g/L of glucose in saturated benzoic acid (5g/L) would be needed to make a litre of 8.33 mmol/L working standard? What would be the concentration in g/L of benzoic acid in the final solution?

(6 marks & 4 marks)

6) Write down the equation for Beer’s Law in terms of a) % transmission b) optical density. State the units of any symbols used.

(6 marks & 4 marks)

7) Calculate the hydrogen ion concentration in nmol/L of solutions of pH 6.9 and 7.6.

(5 marks each)

8) Describe the current definitions for the metabolic syndrome

(10 marks)

9) State the risk factors that are currently used to calculate cardiovascular disease risk.

(10 marks)

10) Given the following patient results calculate the fractional excretion of sodium:-

- Serum:Urine
- Sodium 146 mmol/L 50 mmol/L
- Potassium 4.2 mmol/L
- Chloride 94 mmol/L 57 mmol/L
- Urea 34.4 mmol/L 100 mmol/L
- Creatinine 450 umol/L 3.2 mmol/L
- Osmolality 337 mmol/kg 325 mmol/kg

10 marks)

Exams – Short Answers Autumn 2007

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Course Assessment – Autumn 2007

Short Answer Questions.

Answer all questions.

Time allowed 1 hour.

A maximum of 10 marks will be awarded for each question

The transmittance of a solution of NADH at 340nm is 45%. What is the absorbance of a 1 in 10 dilution of this solution?
List the porphyrias that may present with acute attacks.
Name the enzyme that catalyses the rate limiting step of haem synthesis and the product.
A radioisotope has a half life of 20 days. What percentage of the initial activity is remaining after 10 days and 7 weeks?
A Family Doctor telephones for advice about results on a 24 year old woman with anorexia nervosa. Serum results were:-

- Sodium 141 mmol/L
- Potassium 4.3 mmol/L
- Urea 4.0 mmol/L
- Creatinine 78 umol/L
- Urate 37 umol/L (149-446)
- Bilirubin 2 umol/L
- ALP 73 IU/L (38-126)
- ALT 66 IU/L (<56)
- Iron 6 umol/L
- Transferrin 4.0 g/L
- Transferrin saturation 6%
- TSH 2.5 mU/L (0.5 – 4.2)
- FT4 9.3 pmol/L (10.8-19.3)
- FT3 3.1 pmol/L (3.5 -6.5)

What would you tell him?

A diabetic with a 24 hour creatinine clearance of 25mL/min and a serum creatinine of 180 umol/L was found to have an albumin excretion of 25 ug/min. If the 24 hour urine has a volume of 2000 mL calculate the albumin/creatinine ratio in mg/mmol.
An endomysial antibody assay has been reported to have a diagnostic sensitivity of 88% and a diagnostic specificity of 97% for coeliac disease. What is the probability that a positive result truly indicates coeliac disease in a group of subjects whose pre-test probability of coeliac disease is 1 in 1500?
List 5 ways in which Sickle cell disease may present clinically in adults.
What is the pH of a 0.1 M aqueous solution of an acid of pKa = 4.756 in water at 25^oC? State any assumptions you make.
A Family Doctor telephones you to ask advice about a 53 year old woman with hypertension, truncal obesity and abdominal striae. What diagnosis is most likely and what first line test(s) would you suggest to investigate this potential diagnosis?
Calculate the approximate osmolality of an iv solution of dextrose saline containing 3% w/v glucose and 0.5% w/v sodium chloride

Exams – Spring 2007

admin — Thu, 11 Mar 2010 21:18:01 +0000

Course Assessment – Spring 2007

Essay Questions. Answer 2 questions only. Time allowed 1 hour 30 minutes.

Diabetes mellitus is a genetic disorder. Discuss
Discuss the role of the lab in the support of the Diabetes service.
A 58 year old man attends the clinic and is found to have a serum cholesterol = 7.8 mmol/L and triglycerides = 4.2 mmol/L. Discuss the investigations you would recommend for this patient.
Write an essay on the use of electrophoretic techniques for the diagnosis and management of disease. Include a brief description of the principles of any technique described.

Exams – Autumn 2007

admin — Thu, 11 Mar 2010 21:16:52 +0000

Course Assessment – Autumn 2007

Essay Questions. Answer 2 questions only. Time allowed 1 hour 30 minutes.

Describe the basic components of an HPLC system and outline the main applications of this technique in Clinical Biochemistry.
Discuss the presentation and investigation of patients with suspected anterior hypopituitarism
Write an essay on Iron Homeostasis.
Critically discuss the methods for the detection of point mutations in human genomic DNA

Short Answer Paper June 29th 2007

admin — Fri, 29 Jun 2007 23:06:39 +0000

MSc in Clinical Biochemistry

West Midlands Training Course in Clinical Biochemistry & The University of Birmingham.

Short Answer Paper June 29^th 2007

Answer all Questions

Time Allowed 1 hour 30 minutes

You will need to pass each module

Module 1

1. A 35 year old man has persistent hypertension and hypokalaemia. Following withdrawal of medication and correction of the hypokalaemia, plasma investigations were as follows:

0800h Recumbent 1200h Ambulent

Aldosterone 720 (Ref Range 100-450) 1270 (Ref Range 200 – 800)

pmol/L

Renin 0.1 (Ref Range 1.1-2.7) 0.3 (Ref Range 2.8 – 4.5)

nmol/L/hr

Cortisol 700 300

nmol/L

a. What is the likely diagnosis? 4 marks

b. What is the underlying cause? 4 marks

c. Explain why the serum cortisol is measured? 2 marks

2. A 10 year old boy was investigated for short stature and found to be hypocalcaemic. Further serum investigations showed:

Calcium (mmol/L) 1.81

Phosphate (mmol/L) 1.95

Alkaline Phosphatase(IU/L) 160 (Adult ref range 30-130)

Albumin (g/L) 40

Creatinine (umol/L) 60

Discuss these results and the likely differential diagnosis. 5 marks

Suggest further investigations required for clarification of the diagnosis and indicate what results you would expect for the two likeliest diagnoses. 5 marks

3. List 5 causes of hypophosphataemia. 2 marks each

4. A laboratory wishes to check that its equation for adjusting calcium for albumin is correct for its current methods. A large dataset of paired calcium and albumin results is obtained from the laboratory computer, and a scatter plot of calcium (y-axis) versus albumin (x-axis) is graphed. The linear correlation is confirmed with an equation (in the form of y = mx+c):

Calcium = 0.016 x Albumin + 1.698

a. Using the equation and the desired reference range of 2.10 – 2.60 mmol/L, calculate the adjustment equation for this laboratory, expressed in the form:

Adjusted calcium = calcium + A (B – albumin) 5 marks

What assumptions about the dataset do you need to make for the equation to be valid? 1 mark

b. The equation previously used by the laboratory was

Adjusted calcium = calcium + 0.025(40-albumin).

A patient had the results: Adjusted Ca 2.42 mmol/L, Albumin 25g/L. What would the new adjusted calcium result now be for the same patient? 4 marks

5. Parathyroid hormone has a plasma half life of 3 minutes. A patient undergoing a parathyroidectomy had an initial plasma value of 60 pmol/L. What was the level 20 minutes after isolation of the gland? 5 marks

How long until the PTH level was undetectable? (Limit of detection = 0.2pmol/L) 5 marks

Module 2

6. List 5 differences between type 1 and type 2 diabetes mellitus 2 marks each

7. A 70 year old man with back-pain was referred to a Haematologist because of a low haemoglobin of 10.2 g/dL (ref range 12.5-16.5) and a very high ESR of >100mm/hr (ref range <7). His serum biochemistry is detailed below:

Calcium (mmol/L) 3.16

Alkaline Phosphatase (IU/L) 110 (Ref Range 30-130)

Protein (g/L) 116

Albumin(g/L) 30

Creatinine (umol/L) 160

Parathyroid hormone (pmol/L) 0.2(Ref Range 0.5-5.5)

a. Discuss the results and suggest the likely cause of the abnormalities shown. 6 marks
b. What additional investigations should be undertaken to determine the diagnosis? 4 marks

8. The following plasma glucose results (mmol/L) were obtained on venous samples taken during a 75g oral glucose tolerance test. Interpret the results in the light of the WHO criteria.

Fasting 2 hour Symptoms

Case 1 6.0 7.7 None

Case 2 6.5 11.1 None

Case 3 6.3 7.5 None

Case 4 6.9 15.0 Polyuria/Polydipsia

Case 5 6.4 7.9 None

2 marks each

9. Calculate the LDL concentration in a male patient with the following serum lipid concentrations:

Total Cholesterol (mmol/L) 5.8

Triglycerides (mmol/L) 2.6

HDL Cholesterol (mmol/L) 1.3

8 marks

Briefly discuss the conditions under which LDL cholesterol calculations are invalid. 2 marks

10. A new screening test for diabetic nephropathy is positive in 97% of patients with the disease and 1% of patients without it. Calculate the probability that a patient with a positive test has the disease if the prevalence of the disease in those tested is

a. 1 in 3 5 marks
b. 1 in 100 5 marks

Module 3

11. The following results were obtained in a 50 year old diabetic with oedema after a 12 hour fast.

Serum Sodium (mmol/L) 138

Potassium (mmol/L) 3.6

Urea (mmol/L) 7.1

Creatinine (umol/L) 125

Albumin (g/L) 18

Glucose (mmol/L) 7.3

Cholesterol (mmol/L) 12

Triglycerides (mmol/L) 3.6

Urine Dipstick Protein +++

Glucose -ve

a. What is the most likely diagnosis? 5 marks
b. What test would help confirm the diagnosis? 3 marks
c. Name the likely underlying cause 2 marks

12. A 40 yr old man with a long history of indigestion was admitted with a three day history of projectile vomiting. Investigations revealed

pH 7.52 (7.36-7.44)

pO₂ 7.9 kPa (9-13)

pCO₂ 8.5 kPa (4-6)

HCO₃ 42 (22-29)

a. What is the underlying acid-base disorder?

b. Explain the PO₂ and PCO₂ results
c. What would you expect the plasma potassium concentration to be?
d. What are the expected urine pH and potassium levels?
e. What is the likeliest cause for the underlying acid-base disorder?

2 marks each

13. Briefly describe the features of the refeeding syndrome

10 marks

14. A diabetic has a 24 hour urine output of 2L, a serum creatinine of 200 umol/L and a urine creatinine of 10mmol/L. Calculate the creatinine clearance.

10 marks

15. Calculate the pH of a solution formed by mixing 8mL of KH2PO4 (0.06M) and 12mL Na2HPO4 (0.06M). The pK for the H2PO4- H+ + HPO4 2- is 6.8.

10 marks

Essay Paper 29th June 2007

admin — Fri, 29 Jun 2007 22:07:32 +0000

MSc in Clinical Biochemistry

West Midlands Training Course in Clinical Biochemistry & The University of Birmingham

Essay Paper 29th June 2007

Please answer one question from each module.

You will need to pass each module

Module 1

1. Discuss the clinical features and laboratory investigation of a patient with hypothyroidism.
2. Critically evaluate the methods used for the measurement of calcium and vitamin D in serum.

Module 2

1. Write short notes on

a. Serum Lipoprotein (a) [Lp(a)]

b. ischaemia modified albumin

c. The LDL receptor.

2. Discuss the laboratory investigation of a patient with paraproteinaemia.

Module 3

Discuss critically the methods available for measuring and estimating glomerular filtration rate
Discuss the role of the laboratory in the investigation of a patient with a serum sodium of 118 mmol/L.