The GCT is performed during 24–28 weeks of pregnancy as a routine screening for gestational diabetes.

The patient consumes 50 g of glucose solution, and blood glucose is measured 1 hour later.

No fasting is required before the test.

Clinical uses include:

Screening for gestational diabetes mellitus (GDM).

Identifying women at risk for complications during pregnancy (e.g., macrosomia, pre‑eclampsia).

Guiding further diagnostic testing (Oral Glucose Tolerance Test – OGTT).

If the GCT result is abnormal, a confirmatory OGTT is performed.

Analyte: Blood glucose concentration after 50 g glucose load.

Normal Result: < 140 mg/dL at 1 hour.

Abnormal Findings:

≥ 140 mg/dL → Suggests possible gestational diabetes; requires OGTT for confirmation.

≥ 200 mg/dL → Strongly indicates gestational diabetes.

Clinical Use:

Provides a simple, non‑fasting screening tool for gestational diabetes.

Helps prevent maternal and fetal complications by enabling early intervention.

Supports pregnancy management and monitoring.