Test Code LAB707 Parathyroid Hormone (PTH) Intact with reflex to PTH Related Peptiede (PTHrp)

Important Note

This order will allow screening in hypercalcemic patients with reflex testing of PTHrp in patients with PTH less than 50 pg/mL. This order requires two lavender EDTA tubes (one tube must be on ice).

Performing Laboratory

PTH Intact: Barnes-Jewish Hospital Laboratory

PTHrp: Mayo Clinic Laboratory

BJH Core Laboratory will forward to the performing laboratory. Specimen for PTHrp must be received on wet ice.

Methodology

PTH Intact: Cobas ECLIA electrochemiluminescence

PTHrp: Immunochemiluminometric Assay (ICMA)

Literature References:

Package insert: Parathyroid Hormone. PTH STAT. Roche Corporation 12/2020.

Specimen Requirements

For non hospital patients, call Barnes Jewish Hospital Laboratory Customer Service at 314-362-1470 for STAT pick-up.

Specimen Type: Plasma

Container/Tube: Two Lavender top (EDTA). Place one Lavender top (EDTA) on wet ice for PTHrp testing.

Specimen Volume: Full tube

Day(s) Test Set Up

PTH Intact

Monday through Sunday
Turnaround Time:
STAT: 1 hour after receipt in laboratory
Routine: results available 2-4 hours of receipt

PTHrp

Monday through Thursday

Turnaround Time:

Report availabe 2 to 5 days

Test Classification and CPT Coding

PTH Intact: 83970

PTHrp: 82397

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.

Reference Values

PTH Intact: 15-65 pg/mL

PTHrp: ≤4.2 pmol/L

Literature Reference:

Package insert: Parathyroid Hormone. PTH STAT. Roche Corporation 12/2020.

Specimen Transport Temperature

PTH Intact: Send one tube Ambient

PTHrp: Send the other tube on wet ice

Additional Information

For BJH Laboratory Use Only

PTH Intact

Alternate Tube:

1 red-top tube

Note: Serum obtained from clotted whole blood collected with no anticoagulant or preservative (red-top tube) is not preferred and should be avoided if at all possible. It is acceptable if re-collection is not possible.

Laboratory Processing Instructions:

Test performed in BJH Core Lab. Processed by automated line for delivery to the Cobas 8000. Completed specimens are stored refrigerated for 5 days. For PTH gradient, create 2 PTH orders, comment “grafted” and “non-grafted.”

PTHrp

There is no Alternate Tube for PTHrp testing

Laboratory Processing Instructions:

1. Centrifuge specimen in a refrigerated centrifuge or in chilled centrifuge cups.

2. Aliquot plasma into plastic vial and freeze

Laboratory Ordering Instructions:

When ordering a PTH with reflex to PTHRP in the LIS, a Conditional Lavender on Ice must be added on to the order to enable the PTHrp to reflex when the criteria is met.

Call Laboratory Medicine resident at digital pager 314-747-1320 for approval before sending the specimen.

Mayo Test ID
PTHRP

LOINC Code Information

Name	LOINC Code
Parathyroid Hormone Intact, Plasma	2731-8
Parathyroid Hormone Related Peptide	15087-0

Special Instructions