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Test Code 103R Glucose Cascade

Important Note

The Glucose Cascade automatically reflexes to a Hemoglobin A1c when the glucose result is greater than or equal to 100 mg/dL.

Additional Codes

ALAB: 103R

PowerChart: Not applicable


Specimen Requirement

Glucose:  Fasting is required.

0.5 mL serum or plasma is required.


Hemoglobin A1c:

3mL EDTA whole blood is required

Additional Specimen Collection Information


Collect blood in a lithium heparin, green-top or red-top tube from a fasting patient. (12 hour fast is recommended.) PST and SST (gel tubes) are acceptable. Serum or plasma should be separated from contact with the cells within 2 hours of collection. Specimens not centrifuged within 4 hours of collection may be rejected. Refrigerate the specimen if unable to assay within 8 hours of collection. Hemolyzed specimens are not acceptable. Samples with ≥3+ lipemia must be cleared prior to analysis.


Hemoglobin A1c:

Collect blood in an EDTA; purple-top whole blood is preferred. Lithium heparin, green-top, is also acceptable.


Useful For

Diagnosing and managing diabetes mellitus and other carbohydrate metabolism disorders including gestational diabetes, neonatal hypoglycemia, idiopathic hypoglycemia, and pancreatic islet cell carcinoma


Testing is performed Monday through Sunday.

Routine orders: Typically completed within 4 hours after the specimen arrives at the testing site.

Expedite: Typically completed within 1 hour after the specimen arrives at the testing site.

STAT: Typically completed within 30 minutes after the specimen arrives at the testing site.

CPT Code Information

82947 Chemistry: Glucose Testing Glucose; quantitative, blood (except reagent strip)

LOINC Code Information

1554-5 Glucose [Mass/Volume] In Serum Or Plasma-12 Hours Fasting

Test Method

MercyOne DBQ:

Timed Endpoint; Beckman DXC880i

Mercy DV and MQMA:

Catalytic Oxidation Electrode; iSTAT

Reference Values

Newborn (whole blood or plasma): 50-99 mg/dL

With respect to newborn range there appears to be no accepted standard consensus. This range is set by dr. D. Slagel, laboratory medical director, following consultation with Dr. K. Scott, Neonatologist.

1 Month to Adult (serum, plasma or whole blood): Fasting 70-99 mg/dL

  • Critical values:
    • Low: < 50 mg/dL
    • High: > 450 mg/dL

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