Describe the procedure for the Glucose-6-Phosphate Dehydrogenase Deficiency (G6PD) test.

Procedure for Glucose-6-Phosphate Dehydrogenase (G6PD) Deficiency Test:

1. Blood Sample Collection:

• Begin by collecting a small blood sample from the individual. Commonly, blood is drawn from a vein in the arm using a sterile needle and syringe.

2. Sample Preparation:

• Transfer the collected blood into an EDTA tube to prevent coagulation and maintain the integrity of the sample.

3. Centrifugation:

• Centrifuge the blood sample to separate the red blood cells (RBCs) from the plasma.

4. Washed RBCs Preparation:

• Wash the isolated red blood cells to remove any traces of plasma or contaminants. This step ensures a pure RBC sample for the G6PD test.

5. Incubation with Substrate:

• Incubate the washed red blood cells with a substrate that serves as a G6PD substrate analogue. This substrate is usually a colorless compound that changes color upon enzymatic reaction.

6. Measurement of Enzymatic Activity:

• Assess the enzymatic activity of G6PD by measuring the rate of substrate conversion. G6PD is responsible for converting glucose-6-phosphate to 6-phosphogluconolactone in the presence of NADP+.

7. Spectrophotometry:

• Utilize a spectrophotometer to measure the change in absorbance of the reaction mixture over time. The increase in absorbance corresponds to the enzymatic activity of G6PD.

8. Comparison with Standard Curve:

• Compare the obtained absorbance values with a standard curve generated using known concentrations of the substrate. This comparison allows the determination of G6PD activity in the patient's sample.

9. Interpretation of Results:

• Based on the measured G6PD activity, the individual's status is classified as G6PD-normal or G6PD-deficient. G6PD deficiency is characterized by a lower enzymatic activity compared to the normal range.

Notes:

• This test is crucial for identifying G6PD deficiency, an X-linked genetic disorder affecting the red blood cells' ability to handle oxidative stress.

• The procedure may vary slightly depending on the specific assay or kit used, but the fundamental steps involve measuring G6PD enzymatic activity in the blood sample.

Caution:

• G6PD testing is often done before certain medical treatments, as some medications or infections can trigger hemolysis in individuals with G6PD deficiency.

Performing the G6PD test helps diagnose the deficiency and guides appropriate medical management to avoid potential hemolytic reactions triggered by certain drugs or infections in affected individuals.