CLINICAL CHEMISTRY EXAM BEST QUESTIONS WITH VERIFIED ANSWERS GRADED A LATEST UPDATE

1. What are the two most common patient samples that are sent for biochemical analysis? (p2)
Blood and Urine
2. A) State the two most common uses of biochemical tests on patients. (p2)
1) To diagnose Disease
2) To monitor treatment
B) State the two less common uses of biochemical tests. (p2)
1) Screening for disease
2) Assessing prognosis
3. Once a sample is received in the laboratory and analyzed, how are the results communicated
to the requesting clinician? (p3)
The clinical biochemistry laboratory also provides advice to clinicians on how to make best use
of the service. Medical and scientific personnel are familiar with the clinical significance and
the analytical performance of the test procedures and will readily advise on the interpretation
of the results.
4. What is the difference between serum and plasma? (p4, and gold box on p5)
Serum, the supernatant obtained from centrifugation of clotted blood collected into a plain
container.
Plasma, the supernatant obtained when blood is prevented from clotting by an anticoagulant.
5. If there is difficulty in obtaining a blood specimen from a patient, why might the results show
an elevated serum potassium level? (p4)
Difficulty in obtaining a blood specimen may lead to haemolysis (break-up of red blood cells),
with consequent release of potassium and other red cell constituents. Any cell that breaks will
release potassium.
6. A) Many biochemical results are reported as concentrations in molar units (i.e. mmol/L or
umol/L). Changes in concentration can occur for two reasons. What are they?
1) The amount of the analyte can increase or decrease.
2) The volume of fluid in which the analyte is dissolved can similarly change.
B) What does ‘hyponatremia’ mean?
Hyponatremia is a low sodium concentration in the blood. It is generally defined as a sodium
concentration of less than 135 mmol/L.
C) State the two reasons why it might develop in a patient?
Either too little sodium or too much water.