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EPIC CODE: LAB169 2 HR GLUCOSE TOLERANCE TEST (NON-GESTATIONAL)

Additional Codes

SUNQUEST: GTT2H

Specimen Requirements

Patient Preparation:

Patient should fast for at least 8 hours prior to collect of fasting specimen

Collect:

Collection Container/Tube:

Collect  2 timed specimens (fastings and 120 minutes) Methodist:  Gray Top tubes, Pekin and Proctor  (Green) Lithium Heparin

Collection Instructions:

  • if collected in green top tubes then separate serum from cells ASAP or within 2 hours of collection
  • Send both tubes at Room Temperature

Stability: (storage/transport temperature)

METHODIST
Ambient (room temperature) 24 hours
Refrigerated 7 days
Frozen Unacceptable
   
PEKIN & PROCTOR
Ambient (room temperature) 8 hours
Refrigerated 72 hours
Frozen unaccepatable

Unacceptable Specimen:

Gross hemolysis, unspun gold top tubes or greater than 2 hours of collection

Ordering

  Days Performed:            Daily

Methodology:                 Bicromatic endpoint

Components

Glucose

Resulting

Two hour post 75 g load glucose results should be interpreted as follows:

<140 mg/dL = Normal glucose tolerance
>140 mg/dL and <200 mg/dL = prediabetes
>/= 200 mg/dL  = provisional diagnosis of diabetes, to confirm, recomend repeat testing on subsequent day.

Ref:  ADA 2020 Guidelines on Diagnostic and Classification on Diabetes Mellitus.

CPT Code Information

82951