Mayo Test Catalog, (Sorted By Test Name) - Mayo Medical ...

CAVPC
83900
reabsorption in the proximal tubule is affected by tubular sodium concentration, whereas PTH induces
calcium uptake in the distal tubule and the collecting duct. Excess is excreted in the urine and the feces.
Because PTH increases renal tubular reabsorption of calcium, one would expect patients with
hyperparathyroidism to be hypocalciuric. However, high urinary calcium/creatinine ratios were found in
most hyperparathyroid patients, and less frequently in patients with hypercalcemia due to other causes.
Useful For: Identification of abnormal physiologic states causing excess or suppressed excretion of
calcium, such as hyperparathyroidism, vitamin D abnormality, diseases that destroy bone, prostate cancer,
and drug treatment, such as thiazide therapy
Interpretation: Increased urinary excretion of calcium accompanies hyperparathyroidism, vitamin D
intoxication, diseases that destroy bone (such as multiple myeloma), metastasis from prostatic cancer, and
following calcium supplementation. Patients with absorptive hypercalciuria (increased gut absorption)
will have lowered urine calcium with dietary restriction and, therefore, can be differentiated from patients
with hypercalciuria caused by hyperparathyroidism, hyperthyroidism, Paget's disease, or "renal leak" type
of calciuria as seen in renal tubular acidosis. Thiazide drugs tend to reduce excretion of calcium. For
individuals consuming an average daily intake of 600 mg to 800 mg of calcium per day, the normal daily
excretion of calcium is: -Males: 25 mg to 300 mg -Females: 20 mg to 275 mg The normal adult urine
calcium/creatinine ratio is 350 mg/specimen
*Values are for persons with average calcium intake (ie, 600-800 mg/day).
CALCIUM/CREATININE RATIO
0-12 months: