Martin Health System Stuart, Florida Laboratory Services

1-Hour Glucola Test for Gestational Diabetes

Diabetic Screening in Pregnancy

Principle

Screening for gestational diabetes should be performed between 24 and 28 weeks of pregnancy on all pregnant women NOT previously identified as diabetic. Gestational diabetic screening is performed by glucose measurement in the plasma after a 50 gram glucose load is given without regard to the time of day or time of last meal.

Patient Preparation

A diet containing a minimum of 150 grams of carbohydrate per day should be eaten for at least three days prior to the test.

The patient DOES NOT need to fast on the day of the test. The glucola is given without regard to the time of day or time of last meal.

During the test, smoking should be avoided.

The patient cannot eat or drink anything but water once the glucola is administered until the test is complete.

Reagent

Glucose Tolerance Beverage 50 grams

Procedure

1. Give the patient 50 grams of glucola. The glucose beverage should be consumed within 5 minutes. The patient should remain at rest and avoid medications, smoking, caffeine and alcohol for the duration of the test.

2. Obtain blood glucose sample one hour after the patient finishes drinking the glucose tolerance beverage.

CLM.16 1-Hour Glucola Test for Gestational Diabetes- cont 2

Reference Ranges

Reference ranges based on current recommendations by the American Congress of Obstetricians and Gynecologists:

Glucose load: 50 gram glucose drink

Normal screen: < 140 mg/dL Abnormal, 3 hr Gestational GTT recommended: ≥140 mg/dL

Notes

A glucose screen result of >139 mg/dL after a 50 gram load identifies approximately 80% of women with gestational diabetes mellitus, while the sensitivity is further increased to approximately 90% by a threshold >129 mg/dL. A diagnostic 100 gram oral glucose tolerance test (3 hour GTT, Gestational, LAB3334) is recommended on a separate day for women who exceed the chosen threshold on a 50 gram screening.

References

Burtis, Carl A. and Edward R. Ashwood; Tietz textbook of clinical chemistry; 2nd Edition; W.B. Saunders Co., Philadelphia, PA; 1994; pp. 952-953.

The American College of Obstetricians and Gynecologists, “Gestational Diabetes, “ Obstet Gynecol, 2001, 98(3):525-38. PubMed 11547793.

The American College of Obstetricians and Gynecologists, “Screening and Diagnosis of Gestational Diabetes Mellitus,” Obstet Gynecol , 2011, 118(3):751-3. PubMed 21860317.

American Diabetes Association, “Standards of Medical Care in Diabetes – 2011,” Diabetes Care, 2011, 34(Supp; 1):S11-61. PubMed 21193625.

CLM.16

1-Hour Glucola Test for Gestational Diabetes- cont 3

CLM.16