Glucose, Gestational Screen (50g), 140 Cutoff
Also known as: Glucose, Gestational Screen, Gestational, Glucose
Use
This test is the first‐step screening test for gestational diabetes mellitus (GDM), typically performed between 24 and 28 weeks of pregnancy. It involves administration of a 50 g glucose load, with measurement of blood glucose one hour later. A result ≥ 140 mg/dL indicates abnormal glycemic response and the need for a diagnostic glucose tolerance test (e.g., 3‑hour OGTT)([questdiagnostics.com](https://www.questdiagnostics.com/healthcare-professionals/about-our-tests/womens-health/pregnancy-and-fertility/pregnant-patients/testing-for-each-trimester?utm_source=openai)).
Special Instructions
Not provided.
Limitations
This screening test does not diagnose GDM—it identifies individuals at risk. False negatives may occur, particularly if performed under non‑standard conditions. Sensitivity and specificity vary; lower glucose cutoffs increase sensitivity but reduce specificity. Interpretation should be in clinical context, and abnormal results require follow‑up testing([uspreventiveservicestaskforce.org](https://www.uspreventiveservicestaskforce.org/uspstf/recommendation/gestational-diabetes-screening?utm_source=openai)).
Methodology
Automated Analyzer (Clinical Chemistry)
Biomarkers
Glucose
Analyte
Result Turnaround Time
0 days
Related Documents
For more information, please review the documents below
Specimen
Plasma
Volume
Not provided
Minimum Volume
Not provided
Container
Fluoride/oxalate (gray‑top) tube preferred; whole blood in fluoride/oxalate, green‑top or SST acceptable
Collection Instructions
One‑hour timed specimen after 50 g glucose ingestion; fasting not required; remove plasma/serum from cells immediately
Storage Instructions
Serum/plasma: room temperature; whole blood: refrigerated
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 7 days (sodium fluoride plasma); serum: 4 days |
| Refrigerated | 7 days (plasma and serum) |
| Frozen | 28 days (serum and plasma) |
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