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Epic Test Code LAB3583 Glucose 1 Hour Challenge Test (Antepartum or Postpartum Women)

Performing Location(s)

BMC,FOX,FTT,CRH,LFH,OCH,FCC,HRK

Specimen Type

Serum or Plasma

Preferred Container

Gold or Red top tube

Alternate Container

Green or Gray top tube

Minumum Volume to Submit for Testing

0.5 mL Serum or Plasma

  • Multiple test can be performed from this volume. For question please contact the lab at 547-3975

Transportation Needs

 Deliver specimen to laboratory within 1 hour of collection if unspun. If not possible see "storage Requirements". 

Storage Requirements

Sample tubes should be centrifuged within 2 hour of collection followed by transfer of the serum (red or gold top) or plasma (green top) to a labeled plastic, aliquot tube.

See Causes of Rejection for temperature requirements.
Gray top tubes do not require centrifugation for transport up to 48 hrs.

Causes for Rejection

Mislabeled or unlabeled specimen
Less than 50% draw for Vacutainer tubes
Stressed patient (surgery, infection, corticosteroids).
>72 hours Refrigerated
> 8 hours Room Temperature
>5 days Frozen
Hemolysis > 500 mg/dL HgB
Lipemia > 700 mg/dL Trig
Bilirubin > 40 mg/dL Bili

Limitations

Glucose will decrease in samples left on the clot, and in tubes other than fluoride (gray top tube) prior to analysis.
Failure to have patients on 3 day high carbohydrate diet may result in a falsely abnormal 1GCT
Capillary collected blood may differ from venous due to contamination from hemolysis or interstitial fluid.

Reference Values

Population Units Reference Range High Critical Value Low Critical Value
All Populations mg/dL 100-135 >450 <40

 

Diagnostic Criteria for Antepartum Screen (1GCT) is any glucose > 135 mg/dl. Acceptable response is </= 135 mg/dL

 

Diagnostic Criteria for Antepartum diabetes following a 1 hour 50g dose of Glucola is > 135 mg/dL

Days of Analysis

All

Additional Information

Patient Preparation:Bassett Healthcare Oral GTT Procedure

Proper preparation of the patient prior to the test also needs to be addressed by the ordering physician and a nurse.
Patient should be active and have adequate food intake with at least adequate carbohydrates (at least 150 g. carbohydrate daily) for 3 days prior to test.
Many drugs interfere. They include steroids, oral contraceptives, diuretics, and antihypertensive drugs including thiazides, furosemide, anticonvulsants, psychoactive drugs, antituberculous agents, and anti-inflammatory drugs including salicylates.
Patient should not be stressed (e.g. following surgery, with infections or on corticosteroids)

 

Additional Information for Clinics ON MIBH Campus:

After Women’s Health administers the 50g dose of Glucola the nurse will send the patient to the Out Patient Laboratory with a paper stating what time the next draw needs to be performed.
The laboratory will be held responsible for releasing the correct orders from UNITY/EPIC and drawing the specimens at the specified time.
In some cases the draw may need to be scheduled with the Laboratory before beginning this test.

 

Additional Information for Clinics OFF MIBH Campus:

The Laboratories will be responsible for administering the 50g dose of Glucola AND releasing the correct orders from UNITY/EPIC and drawing the specimens at the specified time.

In some cases the test may need to be scheduled with the Laboratory before beginning this test.

When Requesting in UNITY/EPIC:

Enter the code which corresponds to the 1 Hour Glucose Challenge Test.

 

Contraindications:
1GCT is contraindicated in the presence of obvious diabetes mellitus.
Emesis may be an indication to cancel the test.

Available STAT

Yes

Alternatives to OGTT

A challenge is not necessary if fasting blood sugar is >126 mg/dL on two occasions or a casual blood glucose > 200 mg/dL on two occasions as these are diagnostic for diabetes.

Includes

No fasting required, Blood glucose following 1 hour post 50g Glucola dose

Methodology

Beckman AU/Dx Series

CPT Code

82950

 

Last Updated

18-Mar-22 KT