Synonyms |
|
PTH
|
Clinical
Indications |
|
Differential diagnosis
of hypercalcaemia.
Assessment of parathyroid activity in patients with chronic renal failure.
Investigation and monitoring of patients with hyperparathyroidism secondary to vitamin D
deficiency or malabsorption.
Investigation of hypocalcaemia.
|
Request
Form |
|
Combined Pathology
Blood form (Yellow/Black)
|
Availability |
|
On request, if
specific criteria met.
|
Specific
Criteria |
|
Investigation
of abnormal calcium
status or monitoring renal bone disease.
|
Patient
Preparation |
|
All GP
and outpatients, except renal patients, should be fasting (10 hours). Calcium levels should be
requested at same time.
|
Turnaround
Time |
|
Same day
(Monday to Friday)
|
Specimen |
|
Serum
|
Volume |
|
2 ml
|
Container |
|
Yellow top (SST) tube
|
Collection |
|
Samples should be
transported to the laboratory within 2 hours of collection.
|
|
Lab. Handling |
|
Primary tube sample must be
analysed within 48 hours. (PTH & analyse; NOPTH & save).
|
Causes
for Rejection |
|
Unlabelled sample.
Delay in sample reaching laboratory. Unnecessary repeat requesting.
|
Reference
Range |
|
1.6 - 6.9 pmol/L for
normocalcaemic
patients. However, most patients are being investigated for abnormal calcium levels and in
non-parathyroid disease PTH levels should reflect calcium status (i.e. high calcium, low
PTH).
In the presence of hypercalcaemia, a clearly
elevated PTH of >7.0 pmol/L is diagnostic of primary hyperparathyroidism, while an
appropriately suppressed result of <2.6 pmol/L virtually excludes primary
hyperparathyroidism but could be due to FBH. Where the PTH is between 2.6 and 7.0 pmol/L,
either primary hyperparathyroidism or FBH is possible and a fasting
calcium excretion
is indicated.
Interpretative
comments are added to reports on patients being investigated for suspected
hyperparathyroid disease.
|
|
Unit
Conversion |
|
To convert from ng/L (pg/mL) to
pmol/L
multiply by 0.106
|