Laboratory Services

Glucose Tolerance, 3 hr

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Updated Test Information:

Test Description
Glucose Tolerance, 3 hr
Test ID
GTT3H
Specimen Type

Serum

Specimen Requirements

GTT 1H
GTT 2H
GTT 3H
GTT F

Alternate Specimen Type

Red, Li-heparin plasma, K2EDTA, NaF/Na2EDTA, KF/Na2EDTA, NaF/K‑Oxalate, SST

Specimen Collection / Processing Instructions

GTT 3H - Administer 100 g glucola. Do not mix with water unless directions on product label indicate to do so. The patient needs to be fasting for this tolerance test. During the test period, the patient should remain inactive and receive nothing by mouth including nicotine products. Small sips of water or ice is permissible. Draw 4 specimens. One at fasting, 1 hour, 2 hour, and 3 hour.

Minimum Sample Volume

1 mL

Pediatric Min. Volume (if applicable)

500 uL

Additional Processing Details

Plasma or serum samples without preservative (NaF) should be separated from the cells or clot within half an hour of being drawn.

Stability

8 hours at 15-25˚C
7 days at 2-8 ˚C
Stability in fluoride plasma: 3 days at 15‑25 °C

Methodology

UV Enzymatic

Estimated TAT

0-2 days

Testing Schedule

Monday-Saturday

CPT Code(s)

82951
82952

Performing Lab

Incyte Diagnostics

LOINC Code(s)

20437-0