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HelpTest Code MG-CR Magnesium/Creatinine Urine Ratio
Useful For
This test is useful in assessing kidney function.
Synonyms/Keywords
Magnesium Creatinine ratio
Specimen Requirements
| Fasting Required | Specimen Type | Preferred Container/Tube | Acceptable Container/Tube | Specimen Volume | Specimen Minimum Volume (allows for 1 repeat) |
Pediatric Minimum Volume (no repeat) |
|---|---|---|---|---|---|---|
| No | Urine, 2nd morning random specimen (collected between 8:00 a.m. and 11:00 a.m.) | 50 mg sulfamic acid aliquot tube | Tube or sage container and acidify with dilute hydrochloric acid to a pH <5 | 10 mL | 5 mL | 2 mL |
Collection/Processing Instructions
Collect a second morning urine, preferably collected between 8:00 a.m. and 11:00 a.m.
Pediatric: For untrained children, collect from 6:00 a.m. - 11:00 a.m.
Adjust urine pH to < 5 with sulfamic acid or dilute hydrochloric acid.
Acceptable, but not preferred: collect without preservative, keep refrigerated. Acidify upon arrival at lab and prior to analysis.
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Urine | Refrigerate | 2 weeks |
Rejection Criteria
Unpreserved urines
Test Components
Magnesium and Creatinine give Magnesium/Creatinine ratio
Reference Range Information
| Performing Location | Reference Range |
|---|---|
| Marshfield | Reference ranges have not been established for magnesium in random urine specimens |
Marshfield Labs Performing Department
Marshfield Labs Chemistry
Performing Information
| Performing Location | Day(s) Test Performed | Analytical Time | Methodology/Instrumentation |
|---|---|---|---|
| Marshfield | Monday through Sunday | Less than 2 hours | Xylidyl Blue Endpoint Assay/ Beckman AU |
CPT Codes
| CPT | Modifier (if needed) |
Quantity | Description | Comments |
|---|---|---|---|---|
| 83735 | Magnesium | |||
| 82570 | Creatinine |
Outreach CPT Codes
| CPT | Modifier (if needed) |
Quantity | Description | Comments |
|---|---|---|---|---|
| 83735 | Magnesium | |||
| 82570 | Creatinine |
Ordering Applications
| Ordering Application | Description |
|---|---|
| Cerner | None |