Final answer:
The Glucose Tolerance Test (GTT) is the predominant screening tool for Gestational Diabetes Mellitus (GDM), used to accurately diagnose diabetes when urine glucose or fasting blood sugar levels are inconclusive.
Step-by-step explanation:
The predominant screening tool for Gestational Diabetes Mellitus (GDM) is the Glucose Tolerance Test (GTT). This test determines how well the body handles glucose and is critical in diagnosing diabetes mellitus. Patients with suspected GDM but normal urine glucose or fasting blood sugar levels undergo GTT to ensure accurate diagnosis. During the GTT, blood glucose levels are measured after ingestion of a glucose-rich beverage, with specific values indicating GDM.
To begin with, the Benedict's reducing sugar test may be used as a preliminary method to detect diabetes by identifying reducing sugars like glucose in urine, which reduce copper to form a colored precipitate. If the Benedict's test is positive for high levels of glucose, further blood sugar estimation is conducted. A confirmed diabetes diagnosis, including GDM, is established when blood glucose levels exceed normal limits after a GTT. If diabetes is established, further tests are performed to determine if it is insulin dependent or independent.