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Test Code LAB90 Hemoglobin A1C

Performing Laboratory

St. Louis Children's Hospital - Chemistry

Specimen Requirements

Patient Preparation: None

Container/Tube  
Preferred: Lavender-top (EDTA) tube
Acceptable: Lavender-top (EDTA) samplette/microtainer
Collection Volume: 1.0 mL (minimum 0.6 mL)

Submission Container/Tube: If specimen is coming from outside facility, send whole blood in original collection container.
Special Instructions: Immediately invert tube gently 8-10 times after collection to ensure proper mixing of blood and anticoagulant (this will avoid specimen clotting). Send to lab promptly.

Sample Rejection

Mislabeled or unlabeled specimens

Clotted specimens

Logistics

Test Availability: Monday-Sunday
Cut-off time: None; performed as received
Turnaround Time: Same day; 2 hours from receipt in performing lab

Reference Values

Reference Interval:

all ages: 4.0-5.6%                                                                                         

Critical Value: None established

Methodology

Turbidimetric Inhibition Immunoassay (TINIA) for hemolyzed whole blood using TTAB (Tetradecyltrimethylammonium Bromide)

Limitations

  • Glycated HbF is not detected by the assay as it does not contain the glycated -chain that characterized HbA1c. However, HbF is measured in the Total Hb assay and as a consequence, specimens containing high amounts of HbF (>10%) may result in lower-than-expected mmol/mol HbA1c values (IFCC) and % HbA1c values (DCCT/NGSP). 

Additional Information

FOR SLCH CORE LABORATORY USE ONLY

Lab Processing Instructions: DO NOT SPIN. Give specimen directly to Chemistry PRO bench
Processed Volume: minimum 0.2 whole blood
Analyte Stability:

Specimen Type Temperature Time
Whole Blood (unprocessed)  Ambient 3 days
  Refrigerated (preferred)    7 days
  Frozen  unacceptable       

Test Classification and CPT Code

83036

LOINC

17855-8

Last Reviewed

06/2025