GLUCOSE, NON-OB TOLERANCE TEST

Mnemonic

GTT3<br>GTT4<br>GTT5

Synonym

Oral Glucose Tolerance Test - 3, 4 or 5-hour Non-OB Oral Glucose Tolerance Test - Glucose Tolerance Time Specified - OGTT - GTT

Includes

Fasting Glucose and 1/2, 1, 2, 3 and an optional 4 or 5 hour glucose post 75 gram load

Guidelines

The 2010 ADA guidelines do not recommend this test. Recommend using the 2-hour non-OB OGTT.

Specimen Collection Requirements

Collect

Plasma, Preferred, one 4 mL gray (sodium fluoride/potassium oxalate) top tube. Also acceptable, Serum or Plasma, one 5 mL gold (SST), 7 mL red or 3 mL mint green (lithium heparin, PST) top tube. The gold and green top tubes must be delivered to the lab immediately.

Handling

Allow serum to clot completely at room temperature (minimum: 30 minutes). Preferably, separate serum or plasma from cells within 1 hour of collection. If unable to spin, preferred specimen is gray (sodium fluoride/potassium oxalate) top tube.

Preferred Volume

0.5 mL per specimen

Minimum Volume

0.3 mL per specimen

Transport

Refrigerated (2-8°C)

Rejection Criteria

Grossly hemolyzed specimens

Stability

Specimens collected using lithium heparin tubes (PST) are stable up to 1.5 days refrigerated (2-8°C) on the primary spun gel tube. AFTER CENTRIFUGING AND SEPARATING FROM CELLS: Ambient (15-25°C): 24 hours; Refrigerated (2-8°C): 7 days; Frozen (-20°C): 1 month

Testing Information

Performed

MON-FRI BY APPOINTMENT

Method

Colorimetry

Referral Lab

Samaritan Health Services Laboratories

Reference Values

Reference Values

Interpretation provided.

CPT Codes

3-hour: 82951, 82952x2<br>4-hour: 82951, 82952x3<br>5-hour: 82951, 82952x4

Last Updated: Thursday, January 5, 2017 03:42:13 AM