Instructions for “Calcium Excretion Study”
This test is used for the differential diagnosis of Hyperparathyroidism and Familial Hypocalciuric Hypercalcaemia. The test investigates how the kidneys are retaining calcium from urine and relate this to the level of Parathyroid Hormone (PTH). The test compares calcium, creatinine and PTH levels in a fasting blood sample with calcium and creatinine levels in a random urine collected at the same time.
Patients can get general information about calcium and PTH tests from “Lab Tests on Line” at http://www.labtestsonline.org.uk/understanding/analytes/calcium/test.html
Clinic Medical & Healthcare Staff Instructions:
- Supply the patient with a urine collection pot and a yellow Monovette urine sample tube.
- The patient needs to fast overnight. If this is not feasible, e.g. because of diabetes please contact the Duty Biochemist, (0118 322 7704).
- Note any medications the patient is taking on the request card
- On the card indicate the specimen types “Fasting Blood and Random Urine” and add “For attention of Mr Lester”.
- Request tests: “Calcium Excretion Study” Blood: U&E, Calcium, PTH Random urine: Calcium & creatinine.
Patient Instructions: Calcium Excretion Test
- Do not eat any food from about 9pm (21:00) on the evening before the test. You can drink water but not other drinks, and especially not milky drinks, until after the specimen collections. If fasting is not possible due for example to you having diabetes please contact the laboratory Duty Biochemist for advice, 0118 322 7704.
- On rising on the morning of the test discard the first urine you pass into the toilet.
- When you need to pass urine for the second time collect this into a container and draw up into the yellow syringe like sample tube. It is ideal if this is done shortly before you attend for the blood test. Write your name and date of birth onto the container and add the date and time.
- After the collection of the blood specimen you can eat as normal. If you normally take any medication first thing in the morning, especially if “with food”, then it is best to delay taking it until eating after the blood test. If you have any doubt or anxiety consult a pharmacist indicating the content of these instructions.
- If you have any questions about this test please contact the Duty Biochemist, 0118 322 7704.