Endogenous PTH (Parathyroid Hormone)

* Note: Read all instructions before collecting the sample
* This is not the same as PTH-related protein (PTHrp)

Background

Parathyroid hormone (PTH) is secreted by the parathyroid glands and is one of the principal regulators of calcium and phosphorus homeostasis. It is released in response to lowered ionised calcium and functions to elevate blood Ca concentration and decrease blood P concentration, increase urinary excretion of phosphate, increase renal tubular reabsorption of Ca, increase the rate of skeletal remodelling and accelerate the formation of active vitamin D. Both hypoparathyroidism and hyperparathyroidism may occur.

Sample Requirements:

There are two alternatives for collection of samples for PTH, depending on availability of a centrifuge and how easy it is to get the sample to VETPATH. Read these instructions carefully and decide which is appropriate prior to sample collection.

If you have a centrifuge

Fast the animal overnight prior to collection.
The animal should not be stressed or excited.
Collect 2 - 5 ml of blood into a plain plastic serum tube.
Record the time at which the sample was collected on the laboratory request form.
Allow the sample to clot at room temperature; it is important that the sample be completely clotted as fibrin strands can interfere with the assay. This should take less than one hour.
As soon as the sample has clotted, centrifuge the blood and remove the serum from the cells.
If sufficient serum is available, divide the sample into approximately 1 mL aliquots and store in plain plastic tubes.
Immediately refrigerate the serum sample(s).
The serum sample(s) must reach Vetpath within 5 hours of collection and must remain at 2-8°C during this period; it is important to plan sample collection so that this requrement can be met (or see 10 below). Make sure the exact time of collection is recorded on the request form.
OR
If it is not possible to get the serum to Vetpath within 5 hours, the serum sample(s) must be frozen and not be allowed to thaw.

To freeze the samples, wrap the tubes in ice packs to contour to the tubes to get rapid and complete freezing. Freeze at least overnight before transport to ensure that it is frozen solid.

Once frozen the plasma, contact Vetpath to alert us that the sample is ready for collection. When the courier is ready to collect the sample, wrap the icepacks in thick paper and place into an esky packed to prevent movement.

As a precaution, keep one of the frozen samples at the practice and send the others to Vetpath.

Without a centrifuge

Fast the animal overnight prior to collection.
The animal should not be stressed or excited.
Collect 2 - 5 ml of blood into a plain plastic serum tube.
Record the time at which the sample was collected; make sure this time is recorded on the laboratory request form.
Transport the sample immediately to Vetpath; the sample must reach the laboratory within an hour of collection.
During this time the sample will clot. It does not need to be chilled, but do not allow the blood sample to be exposed to excessive heat.
The sample must be separated and the serum frozen as soon as the sample arrives at Vetpath.
Do not leave the sample in the after-hours box.
When the sample is delivered to the laboratory, make sure that the reception staff know that the sample is for PTH.