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Test Code LAB129 TSH (Thyroid-Stimulating Hormone)

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 Collection Instructions: 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: 

<4 days: 1.00-25.00 mclUnits/mL
4 days-30 days: 0.50-10.00 mclUnits/mL
≥ 30 days: 0.30-4.20 mclUnits/mL                                                                
TSH concentrations may range up to 100 mclUnits/mL due to surge of TSH production on the frist day of life and then fall gradually to adult levels by one month of age.

Critical Value: none established

 

Methodology

Electrochemiluminescence Immunoassay (ECLIA) sandwich principle

Limitations

  • In rare cases, interference due to extremely high titers of antibodies to analyte-specific antibodies (such as HAMA), streptavidin or ruthenium can occur.

Additional Information

FOR SLCH CORE LABORATORY USE ONLY

Lab Processing 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).

Processed Volume: minimum 0.3 mL plasma/serum

Analyte Stability:

Specimen Type Temperature Time
Whole Blood (unprocessed)  Ambient NA
Plasma/Serum (processed) Refrigerated (preferred) 7 days
  Ambience 24 hours
  Frozen  30 days        

Test Classification and CPT Code

84443

LOINC

11580-8

Last Reviewed

06/2025