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Test Code LAB141 Uric Acid, Blood

Performing Laboratory

St. Louis Children's Hospital Laboratory - Chemistry

Specimen Requirements

Patient Preparation: None

Collection Container/Tube:

Preferred: Mint green-top Lithium Heparin (MNTGRN LiHep) tube

Acceptable: Green samplette/microtainer, plain red-top tube, Gold SST gel tube, or lavender-top (EDTA) tube

Submission Container/Tube: If specimen is coming from outside facility and collected in a microtainer, plain red-top tube, or lavender-top tube aliquot processed sample into a plastic vial for transport (labeling with specimen type).

Specimen Collection Volume: 1.0 mL (minimum 0.6 mL)

Special Instructions: Patients undergoing chemotherapy that are being treated with rasburicase (uricase) should have their specimens transported to the lab on ice to prevent vitro loss of uric acid. Send to lab promptly 

 

Sample Rejection

Mislabled or unlabeled 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: 

< 12 years: 2.0-6.0 mg/dL                                                        
≥ 12 years:  
     Female: 2.5-7.0 mg/dL
     Males: 3.0-8.0 mg/dL

Critical Value: >9.0 mg/dL (all ages)

Critical test results will be called back automatically initially and every 168 hours thereafter.

 

Methodology

Enzymatic Colorimetric (Uricase)

Limitations

  • Calcium dobesilate causes artificially low uric acid results.
  • Dicynone (Etamsylaste) at therapeutic concentrations may lead to false-low results.
  • In very rare cases gammopathy, in particular type IgM (Waldenstrom's macroglobulinemia) may cause unreliable results.

Additional Information

FOR SLCH CORE LABORATORY USE ONLY

Lab Processg Instructions: Centrifuge to separate. If specimen is collected in microtainer, plain red-top tube, or lavender-top tube aliquot sample into a Roche false-bottom tube for testing (labeling aliquot with specimen type).

   NOTE: if specimen is received on ice (because patient is being treated with rasburicase) specimen should be kept on ice and processed at 4° C to prevent in vitro loss of uric acid.

Processed Volume: 0.3 mL plasma/serum

Analyte Stability:

Specimen Type Temperature Time
Whole Blood (unprocessed)  Ambient 24 hours
Plasma/Serum (processed) Refrigerated (preferred) 5 days
  Ambient  2 days
  Frozen  6 months     

Test Classification and CPT Code

84550

LOINC

3084-1

Last Reviewed

06/2025