Calcium / Creatinine Ratio

Blood Sciences Test

Endocrinology Handbook

Endocrine Unit

Imperial College Healthcare NHS Trust

Charing Cross, Hammersmith and St. Mary’s Hospitals

Updated: March 2010

Elevated corrected Ca²⁺.
Low PO₄^3-.
Normal alkaline phosphatase.
Normal or elevated serum PTH.
Exclude vitamin D deficiency
High 24 hr urinary Ca²⁺.
To exclude Familial Hypocalciuric Hypercalcaemia (FHH), the calcium clearance to creatinine clearance ratio should be > 0.01. This is calculated as follows (for easy calculation see http://www.meeran.info for on-line calculator).

Calcium Clearance

[Urine Calcium (mmol/l) x urine volume (ml)] / [ Serum Calcium (mmol/l) x 1440]

Creatinine Clearance (This may be calculated already)

[Urine Creatinine (mmol/l) x urine volume (ml)] / [ Serum Creatinine (mmol/l) x 1440]

Serum creatinine is normally expressed in umol/l and needs to be converted to mmol/l by dividing by 1000.

However, this ratio can be reduced to:

Urine Calcium (mmol/l) x [Serum Creatinine (umol/l) / 1000]

Serum Calcium (mmol) x Urine Creatinine (mmol/l)

Urine calcium 1.0 mmol/l Ratio = 1.0 x [130/1000] = 0.0079

Urine creatinine 6.2 mmol/l 2.65 x 6.2

Serum creatinine 130 umol/l

Serum calcium 2.65 mmol/l

Urine calcium 2.2mmol/l Ratio = 2.2 x [74/1000] = 0.035

Urine creatinine 1.4 mmol/l 3.3 x 1.4

Serum creatinine 74 umol/l

Serum calcium 3.3 mmol/l

Please note this test is not UKAS accredited