Parathyroid Hormone
(PTH)

Sample type

Plasma (EDTA)

Uses

Differential diagnosis of hypercalcemia. PTH is an 84-amino acid peptide hormone that is responsible for the regulation of serum calcium levels within a narrow range.

Diagnosis of parathyroid disease and other diseases of calcium homeostasis; monitoring patients undergoing renal dialysis

Precautions

• This test may exhibit interference when sample is collected from a person who is consuming a supplement with a high dose of biotin (also termed as vitamin B7 or B8, vitamin H, or coenzyme R). It is recommended to ask all patients who may be indicated for this test about biotin supplementation. Patients should be cautioned to stop biotin consumption at least 72 hours prior to the collection of a sample.

• Transfer separated plasma into a plastic transport tube clearly labeled as “EDTA Plasma” and maintain at refrigerated temperature.

Interfering factors

Sedative—hypnotic drug propofol (Diprivan) may give falsely low PTH values. High concentrations of hemolysis, lipemia, and bilirubin should be avoided.

Rapid intraoperative PTH that declines ≥50% from the highest baseline in 10 minutes after resection indicates successful total excision.

Pre-analytical errors

1. Put the specimen at room temperature for a long time; this may affect the result.

The corrective action

If you can’t do the test within a short time, you should put it in the refrigerator (at 4C) to prevent contamination of the specimen.

1. Non-EDTA plasma specimen; gross icterus, and unlabeled specimen

The corrective action

The sample must be rejected and another sample will be requested.

Post-analytical errors

I. reports were sent to the incorrect patient

The corrective action

communication with patient, apologizing for the error, and providing him with the correct report

II. write the wrong name in the report or the wrong results.

The corrective action

If the report is not delivered to the patient and this error is discovered, the correct result or the correct name must be written, but if the report is delivered to the patient, you must communicate with him, apologies to him, and tell him that an error has occurred and replace it with the correct report.

Reference range