T3 Clinical Chemistry

Questions:

1. What are the blood tests that are recommended to be carried out?

2. The rationale behind it.

3. The precautious steps/preparations steps before the recommended tests are carried out.

Clinical Scenario 1:

Recommended Blood Tests:

1. Fasting Blood Glucose
2. HbA1c testing
3. Fasting Lipid Panel (Total cholesterol, LDL, HDL, VLDL, and triglycerides)

Rationale:

1. Blood Glucose: Showing classic signs of chronic hyperglycemia, prediabetes, or diabetes mellitus - blurry vision and slow-healing wounds
2. HbA1c: Measure average plasma glucose over the past 2-3 months
3. Fasting Lipid Panel: Sedentary lifestyle and poor dietary habits heighten the risk of dyslipidemia. Evaluating LDL ("bad" cholesterol), VLDL, and triglycerides helps assess the risk of arteriosclerosis and coronary heart

Precautionary Steps / Preparations:

1. Fasting requirement: The patient must fast for at least 12 hours prior to blood collection for a lipid panel. Water is generally allowed
2. Sample handling: Serum or plasma specimens must be collected properly and can be refrigerated at for several days if analysis is delayed

Clinical scenario 2:

Recommended Blood Tests: 2-hour Oral Glucose Tolerance Test (OGTT) using a 75 g glucose load

Rationale: Gestational Diabetes Mellitus (GDM) Screening: Recommended for all nondiabetic pregnant women between 24-28 weeks of gestation Metabolic and hormonal changes during pregnancy can impair pancreatic cell function and reduce insulin sensitivity of body cells, leading to glucose intolerance

Precautionary Steps/ Preparations: Fasting requirement: Requires an overnight fast of at least 8 hours before the baseline fasting blood glucose is measured

Test administration: After the fasting sample is drawn, the patient must consume a special sweet drink containing a 75 g glucose load, followed by a subsequent blood glucose measurement exactly 2 hours later

Clinical scenario 3: The Fatigued Student with Anemia Symptoms Patient: Ms. Maya, a 22-year-old university student.

Symptoms: Reports chronic, mild fatigue that has persisted for months despite adequate sleep. No heavy menstrual bleeding or dietary restrictions.

Family History: Her mother is a B-Thalassemia carrier, though Ms. Maya has never been formally tested.

Initial Screening: A routine blood test ordered during a university health camp reveals a low hemoglobin level and a markedly low Mean Corpuscular Volume (MCV) indicating microcytic red blood cells

Recommended Blood Tests:

1. Complete Blood Count (CBC): specifically evaluating RBC count, hemoglobin, hematocrit, and MCV
2. Follow-up confirmatory test: Hemoglobin Electrophoresis (to evaluate HbA2/HbF fractions) and serum ferritin

Rationale:

1. To assess oxygen-carrying capacity
2. To detect microcytic red blood cells (low MCV)
3. While both iron deficiency and thalassemia minor present with low MCV, a disproportionately high or normal total RBC count relative to a mildly reduced hemoglobin level points toward a beta-thalassemia trait rather than standard iron deficiency

Clinical scenario 4:

Recommended Blood Tests: Complete Blood Count (CBC) with Differential - measuring total white blood cells and the 5 basic leukocyte types: neutrophils, eosinophils, basophils, lymphocytes, and monocytes

Rationale:

1. To screen, diagnose, and monitor infectious or inflammatory health disorders
2. An elevated total white blood cell count (leukocytosis) indicates an active infection or inflammation
3. Specifically, a marked elevation in neutrophils points toward an active bacterial infection (such as bacterial pneumonia matching his rust-colored sputum), whereas viral infections tend to present

Precautionary Steps / Preparations:

1. Sample type: Whole blood collected in an EDTA tube
2. Timing/Clinical Context: Because leukocyte counts can fluctuate rapidly with acute stress or physical exertion, noting the patient's acute symptoms and vital signs (such as fever) is crucial for accurate interpretation
3. No special fasting is required