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Test Code OBGTT (in EPIC) Print out and use as reqn'n (GGTT, GTS, GTS and GTSP in SQ) Glucose Tolerance Test, Gestational, Plasma

Specimen Type

Blood

Container

gray top

Preferred Volume

4 mL

Offsite Collection Instructions

Refer to Gestational Glucose Tolerance testing protocol in the Glucose Tolerance Testing Collection link
 

Patient must fast at least 10 hours prior to test protocol.  Samples must be labeled with patient name, medical record number and elapsed time since glucose beverage ingestion ingestion (i.e. 60, 120 and 180 minutes).
 

No smoking, gum-chewing, drinking, or eating during test. The patient may imbibe small volumes of water. The patient should remain seated as much of the time as possible.

UCMC Collection Instructions

Refer tp Gestational Glucose Tolerance testing protocol in the Glucose Tolerance Testing Collection link
 

Patient must fast at least 10 hours prior to test protocol.  Samples must be labeled with patient name, medical record number and elapsed time since glucose beverage ingestion ingestion (i.e. 60, 120 and 180 minutes).
 

No smoking, gum-chewing, drinking, or eating during test. The patient may imbibe small volumes of water. The patient should remain seated as much of the time as possible.

Availability

24/7

Turnaround Time

3 hours

STAT Availability

Not Available

Test Usage

The GGTT is a diagnostic test for diabetes in pregnant patients, usually between 24 and 28 weeks of pregnancy. Venous plasma glucose is measured in a fasting patient before and at 1, 2, and 3 hour intervals after an oral dose of 100 gm of glucose.

Test Methodology

Spectrophotometric, enzymatic endpoint

CPT Code

82951, 82952 x3

Minimum Volume

2 mL

Reference Range

Any two results reaching or exceeding the following limits for a 100 gram oral glucose load are generally considered definitive for the diagnosis of gestational diabetes mellitus (GDM); however, exceptions can occur (see references below).:

  • Fasting level 95 mg/dL
  • 1 hour level of 180 mg/dL
  • 2 hour level of 155 mg/dL
  • 3 hour level of 140 mg/dL
     

REFERENCES

1. Gestational diabetes mellitus.Diabetes Care 26 (Suppl 1); S103-S105, 2010.

2. Diagnosis and Classification of diabetes mellitus. Diabetes Care ;2033 (Suppl 1):S62-S69, 2010

Critical Results

Critical value <40 or >500mg/dL

Fee Code

43108, 43375 x3

Test Includes

quantitative glucose in plasma on fasting (10 hours) specimen and specimens collected 1, 2 and 3 hours post ingestion of 100 gram glucose load.