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CLC621S - CLINICAL CHEMISTRY 2B - 1ST OPP - NOVEMBER 2024 |
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n Am I B I A u n I VE Rs I TY
OF SCIEnCE AnDTECHnOLOGY
Facultyof HeaIth, Natural
Resourcesand Applied
Sciences
School of Health Sciences
Department of Clinical
Health Sciences
13 Jackson Kaujeua Street
Private Bag 13388
Windhoek
NAMIBIA
T: +264 61 207 2970
F: +264 61 207 9970
E: dchs@nust.na
W: www.nust.na
QUALIFICATION: BACHELOR of MEDICAL LABORATORY SCIENCES
QUALIFICATION CODE: 08BMLS
LEVEL: 6
COURSE: CLINICAL CHEMISTRY 2B
COURSE CODE: CLC621S
DATE: NOVEMBER 2024
SESSION: 1
DURATION: 3 HOURS
MARKS: 100
FIRST OPPORTUNITY EXAMINATION PAPER
EXAMINER:
MODERATOR:
MR. JAFETIT ILONGA
MRS. FREDRIKAENGELBRECHT
INSTRUCTIONS:
1. Answer all questions on the separate answer sheet.
2. Please write neatly and legibly.
3. Do not use the left side margin of the exam paper. This must be allowed for the
examiner.
4. No books, notes and other additional aids are allowed.
5. Mark all answers clearly with their respective question numbers.
PERMISSIBLE MATERIALS:
1. Non-Programmable Calculator
This question paper consists of 8 printed pages including this front page.
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:SECTION A: MULTIPLE CHOICE
[TOT AL MARKS: 10]
QUESTION 1
[10 MARKS]
Please read each question carefully and select the appropriate letter that corresponds to
your understanding. Each of the questions below individually have a grading of one mark.
1.1) Select the lipoprotein fraction that carries most of the endogenous triglycerides.
(1)
A. VLDL
B. LDL
C. HDL
D. Chylomicrons
1.2) Which of the following enzymes is a transferase?
(1)
A. Alkaline Phosphatase (ALP)
B. Creatine Kinase (CK)
C. Amylase
D. Lactate Dehydrogenase (LD)
1.3) In which type of liver disease would you expect the greatest elevation of Lactate
Dehydrogenase (LD)?
(1)
A. Toxic hepatitis
B. Alcoholic hepatitis
C. Cirrhosis
D. Acute viral hepatitis
1.4) In a non-myocardial cause, as opposed to a myocardial cause, of an increased serum or
plasma Creatine Kinase-MB (CK-MB), which of the following would be expected?
(1)
A. A persistent increase in CK-MB
B. An increase in both the percentage and concentration of CK-MB
C. The presence of increased Troponin I (Tnl)
D. A more modest increase in total Creatine Kinase (CK)than CK-MB
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1.5) Which of the following cardiac markers is consistently increased in individuals who
exhibit unstable angina?
(1)
A. Troponin C
B. Troponin T
C. Creatine Kinase-MB (CK-MB)
D. Myoglobin
1.6) Select the most sensitive marker for alcoholic liver disease?
(1)
A. GLD
B. ALT
C. AST
D. y-Glutamyl transferase (GGT)
1.7) Which enzyme is measured in whole blood?
(1)
A. Chymotrypsin
B. Glucose-6-phosphate dehydrogenase
C. Glycogen phosphorylase
D. Lipase
1.8) Which of the statements below about serum urea is true?
(1)
A. Levels are independent of diet.
B. Urea is not reabsorbed by the renal tubules.
C. High blood urea nitrogen (BUN) levels can result from necrotic liver disease.
D. BUN is elevated in prerenal as well as renal failure.
1.9) Blood ammonia levels are usually measured to evaluate:
(1)
A. Renal failure
B. Acid-base status
C. Hepatic coma
D. Gastrointestinal malabsorption
1.10) Hyperalbuminemia is caused by:
(1)
A. Dehydration syndromes
B. Liver disease
C. Burns
D. Gastroenteropathy
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:SECTION B: SHORT AND STRUCTURED QUESTIONS
TOTAL MARKS: 50
QUESTION 2
[10 MARKS]
A 46-year-old man visited his general practitioner for a consultation, during which a random
lipogram panel was requested. Blood samples were collected immediately after the
appointment for the following tests: total cholesterol, triglycerides, and high-density
lipoprotein (HDL) cholesterol, using a random blood collection method. The following results
were obtained:
• Total cholesterol= 14.9 mmol/L
• HDL cholesterol= 0.98 mmol/L
• Triglycerides= 6.81 mmol/L
•
2.1) Calculate the patients Low-Density Lipoprotein and interpret the results?
(3)
2.2) State the name of the formula used to determine the Low-Density Lipoprotein (LDL)
cholesterol level based on the results provided in question 2.1.
(1)
2.3) With reference to the results, describe why a direct measurement for LDLcholesterol is
preferred over the calculation method.
(4)
2.4) A state-of-the-art laboratory has started offering non-fasting lipid profile to facilitate
the patients. Which of the following cholesterol cannot be determined in non-fasting state,
without significant error?
(2)
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QUESTION 3
[10 MARKS]
34-year-old women was admitted to the intensive care unit of the Windhoek Central
Hospital as she had suffered from severe burns. Arterial blood gas analysis was performed
to assessfor any acid-base disturbance. Her biochemical findings are shown below in Table
1.
Analytes
pH
Partial pressure of Carbon Dioxide
Partial pressure of Oxygen
Bicarbonate
Table 1. Laboratory findings
Results
7.56
3.3 kPa
13.3 kPa
22 mmol/L
Reference Ranges
7.35 - 7.45
4.65 - 6.00 kPa
10.5 - 13.2 kPa
22 - 28 mmol/L
3.1) What the likely diagnosis, briefly explain your reasoning, and state whether
compensation has started.
(3)
3.2) Justify why the following arterial blood gas analysis findings would be consistent with
partially compensated respiratory acidosis?
(3)
• pH: Decreased
• Partial pressure of Carbon Dioxide: Increased
• Bicarbonate: Increased
3.3) State the factors, other than renal function, that affect serum urea levels?
(4)
QUESTION 4
[10 MARKS]
4.1) What is the formula for calculating plasma osmolality, and justify the rationale behind
including specific analytes in this calculation?
(6)
4.2) Differentiate between the concepts of osmolality and tonicity.
(4)
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QUESTION 5
[10 MARKS]
5.1) Compare and contrast the biochemistry laboratory findings between iron deficiency
anaemia and anaemia of chronic disease?
(10)
QUESTION 6
[10 MARKS]
A 22-year-old male was attended to at the Casualty Unit of the Katutura Hospital with
complaints of severe abdominal pain in the upper abdomen for the past 4 to 6 hours. The
man presented with pain radiating to the back and the pain was not relieved by analgesics.
He revealed the history of similar type of symptoms, few days back. He also said that he
consumed alcohol and heavy oily food last night.
Analytes
Serum lipase
Serum amylase
Serum alanine aminotransferase
Serum aspartate aminotransferase
Table 2. Laboratory findings
Results
345 IU/L
223IU/L
661IU/L
55IU/L
Reference Ranges
0 -160 IU/L
40 -140 IU/L
10 - 40 IU/L
8-20IU/L
6.1) Looking at the case study presentation and laboratory findings, what is the probable
diagnosis and explain the clinical utility for testing serum lipase and amylase.
(8)
6.2) What other two other biochemical analytes, and their laboratory findings, that would
also be affected by the condition mention in question 6.1.
(2)
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SECTIONC: CASESTUDIES
(40 MARKS]
QUESTION 7
(15 MARKS]
A 5-year-old girl was taken to the Onandjokwe Lutheran State Hospital because she was
unconscious. Her mother said that about two weeks earlier, the girl had a sore throat and
mild fever and started to feel unwell. In the days before going to the hospital, the girl had
been very thirsty and needed to urinate a lot at night. On the day she was admitted, she
started vomiting, was breathing quickly and deeply, and became very drowsy. When doctors
examined her, they found she was dehydrated, had cold skin, a fruity smell on her breath, a
heart rate of 120 beats per minute, and low blood pressure of 90/60 mm Hg. The patient's
blood and urine biochemical laboratory findings are shown in Table 3.
Analytes
Plasma Glucose
Arterial Blood pH
Sodium
Potassium
Chloride
Urinalysis Results
Analytes
Glucose
Ketone bodies
Table 3. Laboratory findings
Results
28.9 mmol/L
7.02
130 mmol/L
5.9 mmol/L
100 mmol/L
Results
++++
++++
Reference Ranges
3.9 - 5.9 mmol/L
7.35- 7.45
136 - 145 mmol/L
3.5 - 5.0 mmol/L
96 - 108 mmol/L
7.1) State the most likely diagnosis {one mark), describe briefly the reasoning behind your
diagnosis {three marks), and conclude by briefly stating what might be the precipitating
cause of this condition {one mark)?
{5)
7.2) What type of acid-base disorder is the patient experiencing {one mark)? Identify four
other notable clinical conditions that could result in the same metabolic dysfunction. Lastly,
explain why the patient is exhibiting rapid and deep {hyperventilated) breathing {5 marks)?
{10)
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--------
QUESTION 8
[10 MARKS]
A 5 -year-old boy was admitted with severe nosebleeds and abdominal swelling for two days
at the Oshakati State Hospital. He had no previous history of jaundice, abdominal swelling,
or a bleeding disorder. One of his siblings had died at six months of age due to severe
nosebleeds and mild jaundice, with the cause unknown. Examination revealed low-grade
fever, severe icterus, pedal oedema, hepatomegaly, splenomegaly with ascites, and an
ophthalmic examination showed bilateral Kayser-Fleischer (KF) rings. The patient's
laboratory findings are shown in Table 4.
Analytes
Haemoglobin
Prothrombin time (PT)
Serum Total Bilirubin
Serum Aspartate Aminotransferase (AST)
Serum Alanine Aminotransferase (ALT)
Serum Alkaline Phosphatase
Serum Ceruloplasmin Level
Urinary Copper Value
Table 3. Laboratory findings
Results
10.8 g/dL
139 seconds
77 µmol/L
112 IU/L
1201U/L
2000 IU/L
0.04 g/L
1.57 µmol/L
Reference Ranges
12-16 g/dL
9 - 12 seconds
3- 21 µmol/L
8-201U/L
10-401U/L
40-130 IU/L
0.14 - 0.40 g/L
0.157 - 0.472 µmol/L
8.1) What is the most probable diagnosis (one mark) and cause of this condition (three
marks)? Justify your answer using the laboratory findings (six marks).
(10)
QUESTION 9
[15 MARKS]
9.1) Compare and contrast between pre-hepatic, hepatic, and post-hepatic jaundice with
reference to five laboratory findings and their expected outcomes for differential diagnosis?
Please tabulate your answer.
(15)
END OF EXAMINATION PAPER
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