Urinary calcium is

calcium Calcium is a chemical element; it has symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar to it ...

in the

urine Urine is a liquid by-product of metabolism in humans and many other animals. In placental mammals, urine flows from the Kidney (vertebrates), kidneys through the ureters to the urinary bladder and exits the urethra through the penile meatus (mal ...

. It is termed -calcuria or -calciuria as a

suffix In linguistics, a suffix is an affix which is placed after the stem of a word. Common examples are case endings, which indicate the grammatical case of nouns and adjectives, and verb endings, which form the conjugation of verbs. Suffixes can ca ...

Normal amount

In a

urinalysis Urinalysis, a portmanteau of the words ''urine'' and ''analysis'', is a Test panel, panel of medical tests that includes physical (macroscopic) examination of the urine, chemical evaluation using urine test strips, and #Microscopic examination, m ...

, the normal amount of urinary calcium can be measured in amount per time (commonly per 24 hours). It can also be measured in amount per mass of

creatinine Creatinine (; ) is a breakdown product of creatine phosphate from muscle and protein metabolism. It is released at a constant rate by the body (depending on muscle mass). Biological relevance Serum creatinine (a blood measurement) is an impor ...

, which avails for estimating the urinary calcium excretion in a spot urine sample, because urinary

creatinine clearance Assessment of kidney function occurs in different ways, using the presence of symptoms and signs, as well as measurements using urine tests, blood tests, and medical imaging. Functions of a healthy kidney include maintaining a person's fluid ...

is relatively unaffected by differences in

free water clearance In the physiology of the kidney, free water clearance (CH2O) is the volume of blood plasma that is cleared of solute-free water per unit time. An example of its use is in the determination of an individual's state of hydration. Conceptually, free ...

which occurs, for example, in

dehydration In physiology, dehydration is a lack of total body water that disrupts metabolic processes. It occurs when free water loss exceeds intake, often resulting from excessive sweating, health conditions, or inadequate consumption of water. Mild deh ...

and which would distort the interpretation of the urinary calcium in a spot urine sample. Normally, in an average adult, the amount of calcium excreted in the urine is 100–250 mg over a 24-hour period.medscape.com > Urine Calcium: Laboratory Measurement and Clinical Utility
By Kevin F. Foley, PhD, DABCC; Lorenzo Boccuzzi, DO. Posted: 12/26/2010; Laboratory Medicine. 2010;41(11):683-686. © 2010 American Society for Clinical Pathology. In turn citing: *Wu HBA. Tietz Guide to Clinical Laboratory Tests. 4th ed. St. Louis, MO: Saunders, Elsevier; 2006. For those on low-calcium diets, there is normally 50–150 mg/24 hours, while those on a calcium-free diet will have 5–40 mg/24 hours. The following

reference range In medicine and health-related fields, a reference range or reference interval is the range or the interval of values that is deemed normal for a physiological measurement in healthy persons (for example, the amount of creatinine in the blood ...

s are for persons with average calcium intake (600–800 mg/day for adults):

Disorders

An abnormally high amount of urinary calcium is called

hypercalciuria Hypercalciuria is the condition of elevated calcium in the urine. Chronic hypercalciuria may lead to impairment of renal function, nephrocalcinosis, and chronic kidney disease. Patients with hypercalciuria have kidneys that excrete higher levels ...

and an abnormally low amount is called

hypocalciuria Hypocalciuria is a low level of calcium in the urine. It is a significant risk factor for predicting eclampsia in pregnancy. The most common causes for hypocalciuria is either thiazide diuretics or reduced dietary intake of calcium. The other caus ...

References

{{reflist Urine tests