Calcium (urine)

Alternative names, keywords

Urine calcium output, urine calcium/creatinine clearance ratio,  CCCR, fractional excretion of calcium.

Samples required

Sample requirements vary.

For urine calcium: creatinine ratio

plain random urine.

For urine calcium output

24 hour urine collection in acidified container. Instructions for 24h urine collection available here or on UHSussex public site.

For urine calcium/creatinine clearance ratio (CCCR)

24 hour urine collection* in acidified container AND

● 5 mL clotted blood. Smaller tubes are available for paediatric samples.

*a plain random urine sample is accepted, but a 24h collection is preferred.

Test indications

Calcium abnormalities.

Recommended as part of renal stone former investigations.

Test information

CCCR= (urine Ca x serum creatinine)/(adjusted serum Ca x urine creatinine)

Calculation needs serum and urine creatinine in same units.

Factors affecting test performance/ results

Intravenously administered gadolinium-containing MRI contrast media can interfere:  Omniscan^® at supra-therapeutic concentrations only, Optimark^® at therapeutic and higher concentrations.

Results should always be assessed in conjunction with the patient’s medical history, clinical examination and other findings.

Reference range

2.5 - 7.5 mmol/24h with normal food intake
_{Source: Roche Cobas^® Calcium kit insert 2023-09, V9.0}

Urine calcium/creatinine clearance ratio is typically less than 0.01 in familial hypocalciuric hypercalcemia, and greater than 0.02 in primary hyperparathyroidism.
_{Source: Bilezikian JP, Potts JT Jr, Fuleihan Gel-H, et al. Summary statement from a workshop on asymptomatic primary hyperparathyroidism: a perspective for the 21st century.J Clin Endocrinol Metab 2002;87:5353-61
Glendenning P. Diagnosis of primary hyperparathyroidism: controversies, practical issues and the need for Australian guidelines.Intern Med J 2003;33:598-603}

Turnaround time

Within 24h of acidification.

Enquiries

Biochemistry (Automation)