How to Prepare Effectively for Clinical Chemistry Exams

Clinical chemistry is a demanding subject, combining intricate biochemical concepts with practical laboratory applications. Whether you’re a medical laboratory science student, a pharmacy major, or in a related health sciences program, preparing for a clinical chemistry exam requires both conceptual understanding and problem-solving skills. Here are practical strategies to help you get ready and perform at your best.

1. Understand the Core Concepts

Clinical chemistry is not just about memorizing reference ranges or test names; it’s about understanding how biochemical processes relate to human health and disease. Make sure you grasp the basics of metabolism, enzyme activity, electrolytes, acid-base balance, and renal and liver function tests. These concepts are foundational and often serve as the basis for more complex questions.

To solidify your understanding, use textbooks like Tietz Fundamentals of Clinical Chemistry or Clinical Chemistry by Bishop. These sources provide not only the theory but also clinical correlations that are often tested in exams.

2. Master Laboratory Techniques and Instrumentation

Since clinical chemistry is a lab-based subject, expect questions about analytical techniques such as spectrophotometry, electrophoresis, chromatography, and immunoassays. Know the principles behind each method, the instruments used, potential interferences, and troubleshooting steps. Reviewing standard operating procedures (SOPs) and lab manuals can reinforce this knowledge.

Diagrams of instruments and flowcharts of processes can be especially helpful. If available, spend extra time in the lab or attend practical sessions to reinforce your hands-on understanding.

3. Review Clinical Relevance and Interpretation

Exams often test your ability to interpret lab results in a clinical context. For instance, elevated ALT and AST might indicate liver disease—but understanding patterns, ratios, and other supporting tests is crucial. Practice interpreting lab panels (e.g., CMP, LFTs, lipid profiles) and identifying which conditions might cause abnormal results.

Work through case studies or online simulations to apply theoretical knowledge to patient scenarios. This strengthens critical thinking, which is key in both exams and real-world practice.

4. Create a Study Schedule

Don’t cram. Clinical chemistry is content-heavy, so break down your study into manageable chunks. Assign specific days to focus on topics like renal function, carbohydrate metabolism, or quality control. Include regular revision sessions and self-assessment quizzes.

Utilize active learning techniques such as flashcards (especially for test markers and reference ranges), concept maps, and teaching peers. Teaching a topic is one of the best ways to reinforce your own understanding.

5. Use Past Questions and Practice Tests

Reviewing past exam questions helps identify frequently tested areas and question formats. Practice multiple-choice questions (MCQs), fill-in-the-blanks, or case-based short answers, depending on your exam format. Time yourself to build speed and accuracy.

Many online platforms and textbooks offer practice questions with explanations—use these to assess your readiness and pinpoint weak areas.

Final Thoughts

Success in clinical chemistry exams is about a balance of theory, practice, and clinical application. Start early, study consistently, and actively engage with the material. By building a strong foundation and applying your knowledge, you'll be well-prepared to tackle even the most challenging questions.

Watch Out for Updates in Clinical Chemistry

 

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This achievement shows the excellent type of education AUF is providing for its students in the health-allied courses.

Keep up the good work, AUF!

Angeles University Foundation, Angeles City, Pampanga Image credit: AUF

Clinical Chemistry Case Analysis, Questions and Answers

Laboratory tests are performed on a 50-year old lean woman during an annual physical check-up. She has no family history of diabetes or any history of elevated glucose levels during pregnancy. Her laboratory results are the following:

FBS = 90 mg/dL

Cholesterol = 140 mg/dL

HDL = 40 mg/dL

TAG = 90 mg/Dl

THE ANSWERS ARE THE CHOICES THAT ARE IN BLACK LETTERS

QUESTIONS:

1.     The probable diagnosis of the patient is:

            a. myocardial infarction

            b. gestational diabetes

            c. hypercholesterolemia

            d. hyperlipoproteinemia

            e. NIL – APPARENTLY, THE RESULTS ARE NORMAL

2.     What are the risk factors that would indicate a potential risk of this patient developing diabetes?

            1. increased cholesterol value

            2. increased TAG value

            3. decreased HDL value

            4.  increased LDL value

            5. NIL

            a. 1                  b. 1 & 2           c. 1,2 & 3        d. 1, 2, 3 & 4   e. NIL

3.  What would be the proper follow-up tests for this patient?

            a. Repeat FBS and OGTT

            b. Repeat TAG, Chole, HDL

            c. Repeat all tests

            d. Repeat all tests and OGTT

            e. NIL

4.  In this specific case, what would be the most significant test for DM?

            a. 2 HPPT

            b. FBS

            c. OGTT

            d. RBS

            e. NIL

5.  Using the Friedewald formula, the LDL value of a patient with the following results is:

TC = 150 mg/dL, TAG = 90 mg/dL, and HDL = 36 mg/dL:

a.      96 mg/dL

b.      102.69 mg/dL

c.       375 mg/dL

d.      24 mg/dL

e.       NIL

Friedewald formula: Explanation

The Friedewald formula (FF) is an estimation of LDL-c level. It utilizes the following values:

Total Cholesterol (TC), Triglycerides (TG), and high-density lipoprotein cholesterol (HDL-c)

The FF is:

LDL-c (mg/dL) = TC (mg/dL) − HDL-c (mg/dL) − TG (mg/dL)/5

Example is above:

Substituting the given data, you will get:

LDL-c = (150 - 36) - (90/5)

LDL-c = (150 -36) - 18

LDL-c = 96 mg/dL

6.  The reason why the value of glucose is 10-15% lower in whole blood than serum and plasma is:

            a. Glycolysis is more predominant in plasma

            b. Gluconeogenesis occurs only in serum and plasma

            c. Red blood cells consume glucose

            d. Glucose is contained mostly in serum

            e. NIL

7.  The value of 110 traditional units of cholesterol in SI units is:

            a. 1.10 mmol/L

            b. 220 mg/dL

            c. 11.0 mmol/L

            d. 6.105 mmol/L

            e. NIL  - 110 mg/dl  = 2.8446 mmol/l

                                   

           

NOTES:

To convert from mg/dL (Traditional units) to mmol/L (SI units)

For total, HDL, and LDL cholesterol divide mg/dL by 38.67

Example 110 mg/dL to SI units

110 mg/dL/38.67 = 2.8846 mmol/L

For triglycerides divide mg/dL by 88.57

Example 150 mg/dL to SI units

 150 mg/dL/88.57 = 1.69357 mmol/L

To convert from mmol/L to mg/dL

For total, HDL, and LDL cholesterol multiply mmol/L by 38.67

Example 2.0 mmol/L to traditional units (mg/dL)

2.0 mmol/L * 38.67 = 77.34 mg/dL

For triglycerides multiply mmol/L by 88.57

Example 3.2 mmol/L to traditional units (mg/dL)

3.2 mmol/L * 88.57 = 283.424 mg/dL

8.  The normal value of TP in SI units is:

            a. 3.2 – 8.5 g/dL

            b. 3.5 – 6.2 g/L

            c. 32 – 85 g/L OTHER BOOKS SAY IT’S 60 – 80 g/L

            d. 3.3 – 5.3 g/dL

            e. NIL

9.  In protein measurements, Nessler’s reagent is:

            a. double iodide of potassium and mercury

            b. double ions of mercury and iodine

            c. mercury, iodine and potassium

            d. bonds between an anion and a cation

            e. NIL

10.  The following are methods for cholesterol determination, except:

            a. Van Handel and Zilversmit

            b. Pearson McGavak

            c. Schoenheimer and Sperry

            d. Sperry and Webs

            e. NIL

11.  The serum proteins are the following, EXCEPT:

            a. albumin

            b. globulin

            c. fibrinogen

            d. immunoglobulin

            e. NIL

12.  When testing for OGTT, the following precautions should be observed, EXCEPT:

            a. The patient should not be ambulatory

b. The patient should eat only 150 grams of carbohydrates daily for 3 days prior to the test

            c. The patient should fast for 8-12 hours

            d. Strenuous exercise should be avoided

            e. NIL

Blood Gas Analysis Review Questions in Clinical Chemistry

I. MULTIPLE CHOICE (Select the BEST ANSWER)

1.    The ideal anticoagulant for arterial blood gas measurements is:
a.    EDTA
b.    Sodium citrate
c.    Lithium heparin
d.    Potassium oxalate
e.    All of the above
f.    None of the above

2.    The kidneys can compensate for nonmetabolic alkalosis by (excretion, retention) of bicarbonate and (increased, decreased) excretion of NaH2PO4.
a. excretion, increased            e.  None of the above
b. retention, increased
c. excretion, decreased
d. retention, decreased

3.    The normal ratio of carbonic acid to bicarbonate in arterial blood is:
a.     1:10                    d.  20:1
b.    7.4:6.1                    e.  None of the above
c.    1:20

4.    If the patient’s arterial  blood gas results are : pH = 7.15, PCO2= 85 mmHg
HCO3 = 35 mmol/L.  What would be your most likely concusion?
a.    partially compensated nonmetabolic acidosis
b.    partially compensated metabolic acidosis
c.    uncompensated nonmetabolic alkalosis
d.    uncompensated metabolic acidosis
e.    None of the above’

5.    If a patient’s arterial blood gas results are pH= 7.38, PCO2 = 35 mm Hg, HCO3 = 27 mmol/L.  What would be your most likely concusion?
a.    Partially compensated nonmetabolic alkalosis
b.    Partially compensated metabolic alkalosis
c.    Uncompensated respiratory alkalosis
d.    Uncompensated metabolic alkalosis
e.    None of the above

6.    The following are precautions for ABG analysis, except:
a.    The specimen should be collected anaerobically
b.    The best receptacle for collection is a glass syringe pre-treated with heparin
c.    If sample is not to be tested immediately, it should be refrigerated or kept in chilled ice.
d.    The temperature of the patient at the time of collection should be noted and recorded
e.    All of the above
f.    None of the above

II. IN THE TABLE BELOW, FILL IN THE CORRECT CHOICES BY USING THE LETTERS OF YOUR CHOICES.

pH

a.    acidic or decrease
b.    alkaline or increase

Concentrations of HCO3 and PCO2:

a.    HCO3 Normal
b.    HCO3 Increased
c.    HCO3 Decreased
d.    PCO2 Normal
e.    PCO2 Increased
f.    PCO2 Decreased

Resulting Condition

a.    Respiratory alkalosis
b.    Respiratory acidosis
c.    Metabolic alkalosis
d.    Metabolic acidosis

Compensatory Mechanism

a.    Increase retention and decrease excretion of HCO3 , H+ excretion by kidneys
b.    Increase excretion and decrease retention of HCO3, H+ retention by kidneys
c.    Increase retention and decrease excretion of CO2  by the lungs
d.    Increase excretion and decrease retention of CO2 by the lungs

Substance or Condition	pH	HCO3	PCO2	Resulting condition	Compensatory Mechanism
Hysteria
Morphine use
Alcohol intoxication
Hyperventilation
Hypoventilation

         


III. PROBLEM SOLVING:

1.    DETERMINE THE pH of the blood sample, if the TCO2 = 22 mmol/L, and the PCO2 is 20 mm Hg. ( 4 pts.)

2.    DETERMINE THE DCO2 IF the H2CO3 is 1.50 mmol/L. ( 2 pts.)

3.    DETERMINE THE pH if PCO2 = 20 mm Hg and HCO3 = 30 mmol/L. ( 4 pts.)

4.    DETERMINE THE pH if the TCO 2 = 28 mmol/L and the PCO2 = 15 mmHg. (5 pts.)

5.    DETERMINE THE ANION GAP If Chloride = 130 mmol/L,  Sodium = 150 mmol/L and HCO3 = 25 mmol/L ( 3 pts)


V. TRANSCRIPTION: ( 1 PT. EACH) Transcribe the acronyms.

1.    TLA______________________________________________
       
2.    NCCLS____________________________________________
           
3.    NIST______________________________________________
               
4.    POC_______________________________________________
           
5.    GGT_______________________________________________
           
6.    BGA_______________________________________________

7.    UDPGT_____________________________________________

8.    OCT________________________________________________

9.    H-H  Equation_________________________________________

10.    PCO2________________________________________________

11.    ALP_________________________________________________

12.      ACP_________________________________________________

13.    LDH_________________________________________________           

14.    CK___________________________________________________

15.    AST__________________________________________________



ANSWER THE QUESTIONS AND RECORD THEM. COME BACK NEXT WEEK TO CHECK YOUR ANSWERS AGAINST THE KEY ANSWERS.