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
Blood Tube Draw Volume
Min 50% draw volume
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