Parathyroid hormone (PTH)

PTH can be assayed during a parathyroidectomy on an urgent basis (i.e. intra-operative PTH levels) however this must be booked with the laboratory at least a week in advance. Please contact the duty biochemist for further details if access to this service is required.

Sample requirements

• If patient on high dose biotin therapy (>5mg/day) collect sample at least 8 hours after the last dose.
• Two different sample tube types are required, an EDTA sample for PTH and a plain serum sample for simultaneous calcium.
• Draw Gold/RUST top tubes first as EDTA contamination will cause falsely low calcium levels; (please note that if no gold top tube is sent for calcium then PTH will not be assayed.

For adults use a 4mL EDTA tube plus a 5mL gold top gel tube (or rust top for the Acute Unit)

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Storage/transport

Send at ambient temperature to the laboratory.

Required information

Relevant clinical details including current medication.

If patient is receiving high dose biotin (>5mg/d) samples for PTH should be collected at least 8 hours after the last biotin dose.

Turnaround times

The in-lab turnaround time is less than 2 weeks.

The test can be ordered as an urgent request.

Reference ranges

1.6 - 6.9 pmol/L when the patient is normocalcaemic.

Note: PTH levels within this range may be inappropriate when calcium levels are outside the adjusted calcium reference range.

Further information

Page last updated 27/04/2023