Lab Test

PTH, Intra Operative

Intra-Operative PTH, Parathyroid Hormone for the Operating Room (OR PTH)

Test Codes



  • This test is only available to patients in the Operating Room and ordered only by Operating Room staff. Please see the requirements for notification (below) prior to ordering this test:
    • Grosse Pointe and Troy: The Laboratory must be notified 48 hours in advance of the scheduled surgery. It is requested that the surgery is scheduled to begin prior to 11:00 am.
    • Farmington Hills and Royal Oak: It is preferred that the Laboratory is notified 24 hours in advance of the scheduled surgery.
  • For PTH testing on non-OR patients, please see Parathyroid Hormone.

Specimen Collection Criteria

Collect: One Lavender-top EDTA tube. (Minimum Whole Blood: 2.0 mL)

  • The baseline Intra-Operative specimen is collected in pre-op prior to surgery. (Order PTH, Baseline in EPIC.)
  • Subsequent Intra-Operative specimens are collected as directed by the surgeon. (Order PTH, Intra-Operative in EPIC.)

Rejection Criteria

  • Hemolyzed specimens.
  • Icteric specimens.
  • Lipemic specimens.
  • Specimens not collected and processed as indicated.

Inpatient Specimen Preparation

Specimens are drawn in the Operating Room. Specimens must be hand delivered to the STAT Laboratory (Royal Oak) or Chemistry Laboratory (Farmington Hills, Grosse Pointe and Troy) immediately after collection.

In-Lab Processing

Centrifuge immediately to remove plasma from cells.


Specimen Stability for Testing:

Room temperature (20-26°C or 68-78.8°F): 8 hours
Refrigerated (2-8°C or 36-46°F): 72 hours
Frozen (-20°C/-4°F or below): Not applicable

Specimen Storage in Department Prior to Disposal:

Refrigerated (2-8°C or 36-46°F): 7 days


Farmington Hills Chemistry Laboratory
Grosse Pointe Chemistry Laboratory
Royal Oak STAT Laboratory
Troy Chemistry Laboratory


As scheduled with the Operating Room. Specimens are tested immediately upon receipt in the Laboratory. Results are available within 30 minutes of receipt in the Laboratory.

Reference Range

8-72 pg/mL.

Test Methodology

Chemiluminescent Immunoassay.


A 50% or greater drop in PTH level between a baseline and subsequent post-surgical samples would indicate the successful removal of hyperfunctioning parathyroid tissue.

Clinical Utility

A significant difficulty with parathyroid surgery is the possibility of missing an ectopic hyperfunctioning gland. Prior to surgery a baseline PTH level is drawn. If the PTH does not decrease by 50%, the surgeon may first send a frozen section to confirm that parathyroid tissue was indeed removed, and based on this result explore for an undetected enlarged gland. In most cases intra-operative PTH testing will save surgical time and minimize the need for follow-up surgery.

CPT Codes



Last Updated


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This directory currently reflects information only for specimens collected and/or processed at the
Farmington Hills, Grosse Pointe, Royal Oak, and Troy campuses.