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HelpTest Code CACR3 Calcium/Creatinine Ratio, Random, Urine
Specimen Required
Supplies: Sarstedt Aliquot Tube 5 mL (T914)
Collection Container/Tube: Clean, plastic urine container with no metal cap or glued insert
Submission Container/Tube: Plastic, 5-mL tube or a clean, plastic aliquot container with no metal cap or glued insert
Specimen Volume: 4 mL
Collection Instructions:
1. Collect a random urine specimen.
2. No preservative.
Useful For
Evaluation of calcium oxalate and calcium phosphate kidney stone risk
Calculation of urinary supersaturation
Evaluation of bone diseases, including osteoporosis and osteomalacia
Profile Information
| Test ID | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| CCTR | Calcium/Creat Ratio, Random, U | No | Yes |
| CALC5 | Calcium, Random, U | No | Yes |
| CRETR | Creatinine, Random, U | No | Yes |
Method Name
CALC5: Photometric
CRETR: Enzymatic Colorimetric Assay
Reporting Name
Calcium/Creat Ratio, Random, USpecimen Type
UrineSpecimen Minimum Volume
1 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Urine | Refrigerated (preferred) | 14 days | |
| Frozen | 30 days | ||
| Ambient | 72 hours |
Reference Values
1 month-<12 months: 0.03-0.81 mg/mg creatinine
12 months-<24 months: 0.03-0.56 mg/mg creatinine
24 months-<3 years: 0.02-0.50 mg/mg creatinine
3 years-<5 years: 0.02-0.41 mg/mg creatinine
5 years-<7 years: 0.01-0.30 mg/mg creatinine
7 years-<10 years: 0.01-0.25 mg/mg creatinine
10 years-<18 years: 0.01-0.24 mg/mg creatinine
18 years-83 years: 0.05-0.27 mg/mg creatinine
Reference values have not been established for patients who are less than 1 month of age.
Reference values have not been established for patients who are greater than 83 years of age.
Interpretation
Increased urinary calcium excretion (hypercalciuria) is a known contributor to kidney stone disease and osteoporosis.
Many cases are genetic (often termed "idiopathic"). Previously such patients were often divided into fasting versus absorptive hypercalciuria depending on the level of urine calcium in a fasting versus fed state, but the clinical utility of this approach is now in question. Overall, the risk of stone disease appears increased when 24-hour urine calcium is greater than 250 mg in men and greater than 200 mg in women. Thiazide diuretics are often used to reduce urinary calcium excretion and repeat urine collections can be performed to monitor the effectiveness of therapy.
Known secondary causes of hypercalciuria include hyperparathyroidism, Paget disease, prolonged immobilization, vitamin D intoxication, and diseases that destroy bone (such as metastatic cancer or multiple myeloma).
Urine calcium excretion can be used to gauge the adequacy of calcium and vitamin D supplementation, for example in states of gastrointestinal fat malabsorption that are associated with decreased bone mineralization (osteomalacia).
Clinical Reference
1. Fraser WD. Bone and mineral metabolism. In: Rifai N, Horwath AR, Wittwer CT, eds. Tietz Textbook of Clinical Chemistry and Molecular Diagnostics. 6th ed. Elsevier; 2018:1438
2. Curhan GC, Willett WC, Speizer FE, Stampfer MJ. Twenty-four-hour urine chemistries and the risk of kidney stones among women and men. Kidney Int. 2001;59:2290-2298
3. Metz MP. Determining urinary calcium/creatinine cut-offs for the pediatric population using published data. Ann Clin Biochem. 2006;43:398-401
4. Pak CY, Britton F, Peterson R, et al. Ambulatory evaluation of nephrolithiasis. Classification, clinical presentation and diagnostic criteria. AM J Med. 1980;69:19-30
5. Pak CY, Kaplan R, Bone H, et al. A simple test for the diagnosis of absorptive, resorptive and renal hypercalciurias. N Engl J Med. 1975;292:497-500
Performing Laboratory
Mayo Clinic Laboratories in Rochester
Test Classification
This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.CPT Code Information
82310
82570
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| CACR3 | Calcium/Creat Ratio, Random, U | 9321-1 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| CCTR | Calcium/Creat Ratio, Random, U | 9321-1 |
| CALC5 | Calcium, Random, U | 17862-4 |
| CRETR | Creatinine, Random, U | 2161-8 |
Day(s) Performed
Monday through Sunday
Report Available
1 to 3 daysForms
If not ordering electronically, complete, print, and send a Renal Diagnostics Test Request (T830) with the specimen.