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Test Code GTT5HR Glucose, Tolerance, 5 Hour Hypoglycemia (GTT)

Specimen Collection Information

Specimen  Min. Test Volume Collection Container Special Handling
Blood 0.1 mL Light Green (lith. heparin) top
Gold top
Marble Red top
 

Reference Ranges & Critical Values

Assay Gender Age Range Normal Range Critical Values Units
GTT5HR ALL 0 Minutes – 150 Years

Results interpreted by Physician

<45
>500
mg/dL

Collection Instructions

Refer to Glucose Tolerance Protocols for additional instructions.

 

  1. Confirm that the patient has fasted 10-16 hours.

  2. Collect urine sample and run dipstick urine test. If test is positive, consult physician to determine whether to continue tolerance test.

  3. Draw fasting blood sample in green top tube or use hemmocue finger stick. Save 1 mL of serum frozen for possible insulin assay.

  4. Have patient drink 225mL (7.5oz) of Dextol Glucose Tolerance Beverage for a dose of 75 grams of glucose. See dosage chart if patient weighs less than 91 lbs. Record time.

  5. Patient should be instructed to continue fasting with limited physical activity for the duration of the test. Monitor patient during test for symptoms of hypoglycemia.

  6. If symptoms appear, notify physician. Insulin and glucose levels determined at the time of symptoms are most diagnostic. Physician should determine whether to obtain sample at this time and/or continue test.

  7. Draw blood samples 1, 2, 3, 4 and 5 hours from the time the Dextol was given. Save 1 mL of serum from each specimen frozen for possible insulin assay.

 

 

Specimen Stability

3 days at 2-8°C

Day(s) Performed

Monday - Sunday

CPT

82951 + 82952

 

LOINC

50588-3