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Test Code GLU.CHAL GLUCOSE, 1 HR CHALLENGE

Methodology

Colorimetric

Useful for establishing a provisional diagnosis of gestational diabetes in at-risk pregnant women. Abnormal results must be confirmed by GTTG “Glucose Tolerance, Gestational, Plasma or Serum.”

Specimen Requirements

 

Procedure:

  1. Administer 50 g oral dose of glucose tolerance beverage.
  2. After 1 hour, draw blood specimen.

 
Specimen Collection:
Submit only 1 of the following specimens:

 

Preferred:

Plasma

Container/Tube: Green-top (lithium heparin) tube(s) or grey-top (potassium oxalate/sodium fluoride) tube(s)

Specimen Volume: 1 mL (minimum volume: 0.5 mL) of plasma

Grossly hemolyzed specimen is not acceptable.

 

Collection Instructions: Spin down within 1 hour of draw.

Note:

  1. Grey-top tube is stable for 24 hours after drawing specimen.
  2. Label specimen appropriately (plasma).

 

Alternate:

Serum

Serum Gel Tube

Container/Tube: Serum gel tube(s)
Specimen Volume: 1 mL (minimum volume: 0.5 mL) of serum-Grossly hemolyzed specimen is not acceptable.

Collection Instructions: Spin down within 1 hour of draw.

Note: Label specimen appropriately (serum).

 

Alternate:

Serum

Plain, Red-Top Tube

Container/Tube: Plain, red-top tube(s)
Specimen Volume: 1 mL (minimum volume: 0.5 mL) of serum-Grossly hemolyzed specimen is not acceptable.

Collection Instructions: Spin down within 1 hour of draw.

Note: Label specimen appropriately (serum).

Day(s) Test Set Up

Monday through Sunday

Reference Values

<130 mg/dL

A 1-hour post-load glucose of >130 mg/dL identifies 90% of patients with gestational diabetes. An abnormal challenge must be confirmed by a 3-hour glucose tolerance test.

Critical values (automatic call-back): <50 mg/dL or >500 mg/dL

Performing Laboratory

Logan Health Medical Center-Chemistry

Test Classification and CPT Coding

82947

Specimen Transport Temperature

Refrigerate