Understanding GTT Rates Calculator: Interpreting Glucose Tolerance Test Results
A Glucose Tolerance Test (GTT), specifically the Oral Glucose Tolerance Test (OGTT), is a standard medical diagnostic procedure used primarily to screen for diabetes and, very commonly, Gestational Diabetes Mellitus (GDM) during pregnancy. The test measures how well your body is able to regulate glucose (sugar) after consuming a specific amount of carbohydrates.
When people search for a "GTT rates calculator," they are usually looking for a tool to help interpret the blood sugar levels returned by the lab at different time intervals during the test. These levels are not interest rates or financial figures; they are metabolic rates of glucose clearance measured in milligrams per deciliter (mg/dL) or millimoles per liter (mmol/L).
How the GTT Works
Typically, for a standard 75g OGTT used in pregnancy screening, the process involves:
- Fasting Draw: Blood is drawn after an overnight fast (usually 8-12 hours) to establish a baseline fasting glucose level.
- Glucose Drink: The patient drinks a standardized solution containing 75 grams of glucose.
- Subsequent Draws: Blood is drawn again exactly one hour and two hours after finishing the drink.
Interpreting the "Rates" (Thresholds)
The calculator below helps interpret standard 2-hour, 75g OGTT results based on widely accepted criteria, such as those from the International Association of Diabetes and Pregnancy Study Groups (IADPSG). Different healthcare providers or regions may use slightly different thresholds.
For Gestational Diabetes diagnosis using these criteria, GDM is typically diagnosed if any one of the following blood glucose threshold values is met or exceeded:
- Fasting: ≥ 92 mg/dL
- 1-Hour: ≥ 180 mg/dL
- 2-Hour: ≥ 153 mg/dL
Disclaimer: This tool is for informational purposes only. It does not provide medical advice or diagnosis. Always consult your doctor or healthcare provider to interpret your specific test results and discuss the next steps.
GTT Result Interpreter (Standard 75g OGTT)
Enter your glucose levels in mg/dL below. Leave blank if a specific time point was not measured.
- ";
// Evaluate Fasting
if (!isNaN(fastingVal)) {
if (fastingVal >= fastingThreshold) {
elevatedCount++;
detailsHTML += "
- Fasting: Elevated (" + fastingVal + " mg/dL indicates ≥ " + fastingThreshold + " threshold). "; } else { detailsHTML += "
- Fasting: Normal range (" + fastingVal + " mg/dL is < " + fastingThreshold + "). "; } } // Evaluate 1-Hour if (!isNaN(oneHourVal)) { if (oneHourVal >= oneHourThreshold) { elevatedCount++; detailsHTML += "
- 1-Hour: Elevated (" + oneHourVal + " mg/dL indicates ≥ " + oneHourThreshold + " threshold). "; } else { detailsHTML += "
- 1-Hour: Normal range (" + oneHourVal + " mg/dL is < " + oneHourThreshold + "). "; } } // Evaluate 2-Hour if (!isNaN(twoHourVal)) { if (twoHourVal >= twoHourThreshold) { elevatedCount++; detailsHTML += "
- 2-Hour: Elevated (" + twoHourVal + " mg/dL indicates ≥ " + twoHourThreshold + " threshold). "; } else { detailsHTML += "
- 2-Hour: Normal range (" + twoHourVal + " mg/dL is < " + twoHourThreshold + "). "; } } detailsHTML += "