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Test Code LAB108 Parathyroid Hormone (PTH) Intact, Blood

Important Note

SPECIMEN MUST ARRIVE IN LAB WITHIN 1 HOUR OF COLLECTION

Performing Laboratory

St. Louis Children's Hospital Laboratory - Chemistry

Specimen Requirements

Patient Preparation: Samples should not be taken from patients receiving therapy with high biotin doses (i.e., >5 mg/day) until at least 8 hours following the last biotin administration

Collection Container/Tube:

Preferred: Lavender-top (EDTA) tube

Acceptable: Plain red-top tube or Lavender-top (EDTA) microtainer

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

Specimen Collection Volume: 2.0 mL (minimum 1.0 mL)

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.

NOTE: this test may NOT be added on to specimen already in lab.

 

Sample Rejection

Specimens collected in gel tubes

Specimens that are hemolyzed

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: 

<18 years: 14-72 pg/mL
≥ 18 years: 15-65 pg/mL                                                                          

Critical Value: None established

 

Methodology

Electrochemiluminescence binding assay - 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.
  • Assay is affected by hemolysis

Additional Information

FOR SLCH CORE LABORATORY USE ONLY

Lab Processing Instructions: Centrifuge to separate. Aliquot sample into a Roche false-bottom tube for testing (labeling aliquot with specimen type).

NOTE: test may NOT be added on to specimen already in lab

Processed Volume: minimum 0.3 mL plasma/serum

Analyte Stability:

Specimen Type Temperature Time
Whole Blood (unprocessed)  Ambient NA
Plasma/Serum (processed) Refrigerated (preferred)    3 days
  Ambient  4 hours    
  Frozen  6 months    

Test Classification and CPT Code

83970

LOINC

2731-8

Last Reviewed

06/2025