Random Blood Sugar (RBS) Test

1. Objective

To measure the glucose level in the blood at any random time of the day, regardless of the last meal, for screening and monitoring diabetes mellitus.

2. Principle

The RBS test was based on the glucose oxidase-peroxidase (GOD-POD) method.

Glucose in the sample was oxidized by glucose oxidase to gluconic acid and hydrogen peroxide.

Hydrogen peroxide then reacted with a chromogen in the presence of peroxidase, producing a color change.

The intensity of the color was proportional to the glucose concentration and was measured spectrophotometrically.

3. Materials

Patient’s blood sample (capillary or venous)

Glucometer with test strips (for bedside test) or spectrophotometer (for lab test)

Glucose oxidase reagent kit

Test tubes, pipettes

4. Procedure

Bedside (Glucometer):

1. A finger prick was performed using a sterile lancet.

2. A drop of blood was placed on the glucose test strip.

3. The glucometer displayed the blood glucose concentration.

Laboratory (GOD-POD method):

1. Venous blood was collected and centrifuged to separate serum.

2. Serum was mixed with glucose oxidase reagent.

3. After incubation, absorbance was measured at 505 nm.

4. The glucose level was calculated using a standard curve.

5. Results (Normal Range)

Normal: < 140 mg/dL (7.8 mmol/L)

Prediabetes: 140 – 199 mg/dL (7.8 – 11.0 mmol/L)

Diabetes: ≥ 200 mg/dL (≥ 11.1 mmol/L)

6. Uses

Screen for diabetes mellitus.

Monitor blood glucose in known diabetic patients.

Assess glucose fluctuations in emergency or routine check-ups.

7. Consultation

High glucose levels suggested possible diabetes mellitus or stress-induced hyperglycemia.

Low glucose levels indicated hypoglycemia, requiring urgent evaluation.

Abnormal results required follow-up with fasting blood sugar (FBS), oral glucose tolerance test (OGTT), or HbA1c for confirmation.

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