11/07/2026
HB Test
Definition
The Hemoglobin (Hb) Test is a laboratory test used to measure the concentration of hemoglobin in the blood. Hemoglobin is the oxygen-carrying protein found in red blood cells. The test is commonly used to diagnose anemia, polycythemia, blood loss, and other blood disorders.
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Principle
The hemoglobin test is based on the conversion of hemoglobin into a stable colored compound, which is measured photometrically. Common methods include the Cyanmethemoglobin Method and the Sodium Lauryl Sulfate (SLS) Method used in automated hematology analyzers.
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Objectives
1. To measure the hemoglobin concentration in blood.
2. To diagnose anemia and polycythemia.
3. To assess blood loss.
4. To monitor treatment of blood disorders.
5. To evaluate the patient's overall health status.
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Materials Required
Whole blood sample (EDTA)
EDTA blood collection tube
Hemoglobin reagent (Drabkin's reagent or SLS reagent)
Micropipettes and tips
Test tubes or cuvettes
Spectrophotometer or automated hematology analyzer
Gloves and PPE
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Procedure
1. Collect 2–3 mL of venous blood in an EDTA tube.
2. Mix the blood gently to prevent clotting.
3. Add the required amount of blood to the hemoglobin reagent.
4. Allow the reaction to occur according to the manufacturer's instructions.
5. Measure the absorbance using a spectrophotometer or automated analyzer.
6. Calculate or obtain the hemoglobin concentration.
7. Record and report the result in g/dL.
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Observation (Reference Values)
Group Normal Hemoglobin
Adult Male 13.5–17.5 g/dL
Adult Female 12.0–15.5 g/dL
Children 11.0–16.0 g/dL
Newborn 14.0–24.0 g/dL
> Reference ranges may vary slightly between laboratories.
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Advantages
Simple, rapid, and accurate.
Essential for diagnosing anemia.
Useful for routine health screening.
Helps monitor treatment response.
Can be performed manually or with automated analyzers.
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Limitations
Results may be affected by dehydration or overhydration.
Hemolysis or improper sample collection may interfere with results.
Does not identify the cause of anemia.
Additional tests (e.g., CBC, hematocrit, iron studies, vitamin B12, and folate) may be required for a complete diagnosis.
Results should always be interpreted together with the patient's clinical findings.
