Glucose is the primary source of energy for the body.

The FBS test evaluates blood sugar levels after at least 8–12 hours of fasting, ensuring accuracy without food influence.

Clinical uses include:

Screening for diabetes mellitus.

Detecting prediabetes (impaired fasting glucose).

Monitoring blood sugar control in diabetic patients.

Investigating causes of hypoglycemia.

The test is performed using a blood sample, typically drawn in the morning.

Analyte: Blood glucose concentration (mg/dL).

Normal Range:

70 – 99 mg/dL → Normal

100 – 125 mg/dL → Prediabetes (Impaired fasting glucose)

≥ 126 mg/dL → Diabetes mellitus (confirmed on repeat testing)

Abnormal Findings:

High FBS: Suggests diabetes or impaired glucose tolerance.

Low FBS: May indicate hypoglycemia due to insulin excess, liver disease, or endocrine disorders.

Clinical Use:

Provides a baseline measure of glucose metabolism.

Helps guide diagnosis, treatment, and monitoring of diabetes.

Often combined with HbA1c and Oral Glucose Tolerance Test (OGTT) for comprehensive evaluation.