Test Details
Methodology
Kinetic Jaffe
Result Turnaround Time
Within 1 day
Use
A renal function test used in eGFR calculation.2
High creatinine: Renal diseases and insufficiency with decreased glomerular filtration, urinary tract obstruction, reduced renal blood flow including congestive heart failure, shock, and dehydration; rhabdomyolysis can cause elevated serum creatinine. Low creatinine: Small stature, debilitation, decreased muscle mass; some complex cases of severe hepatic disease can cause low serum creatinine levels. In advanced liver disease, low creatinine may result from decreased hepatic production of creatinine and inadequate dietary protein as well as reduced muscle mass.3
Specimen Requirements
Test Includes
Creatinine, serum; eGFR calculation
Limitations
With reduced renal blood flow, creatinine rises less quickly than urea nitrogen. Concentration of creatinine only becomes abnormal when about half or more of the nephrons have stopped functioning in chronic progressive renal disease. Antibiotics containing cephalosporin lead to significant false-positive values if samples are drawn within four hours of a dose.4 With severe renal disease, creatinine is not reliable in the presence of cefoxitin therapy. There is less interference reported from the cephalosporins cephalothin, cephaloridine, cephadrine sodium, and cephaloglycin dihydrate. Lipemia, hemolysis, and bilirubin may interfere.5,6
Interfering Endogenous Substances7 | Deviations | Degree of Interference |
|---|---|---|
Pyruvate (serum/plasma) | >2.6 mg/dL | +12.8% |
Glucose (serum/plasma) | >450 mg/dL | +16% |
Ascorbic acid (serum/plasma) | >88 mg/dL | -10.1% |
Urea (urine) | >12612 mg/dL | -11.0% |
Specimen
Serum (preferred) or plasma
Volume
1 mL
Minimum Volume
0.7 mL (Note: This volume does not allow for repeat testing.)
Container
Red-top tube, gel-barrier tube, or green-top (lithium heparin) tube. Do not use oxalate, EDTA, or citrate plasma.
Storage Instructions
Maintain specimen at room temperature.1
Causes for Rejection
Hemolysis; improper labeling
Collection Instructions
Separate serum or plasma from cells within 45 minutes of collection.
Stability Requirements
Temperature | Period |
|---|---|
Room temperature | 14 days |
Refrigerated | 14 days |
Frozen | 14 days |
Freeze/thaw cycles | Stable x3 |
Reference Range
See table.
Age | Female* (mg/dL) | Male (mg/dL) |
|---|---|---|
*Labcorp internal studies. | ||
Age/sex regardless | 0.57−1.00 | 0.76−1.27 |
<2 m | 0.44−1.19 | 0.44−1.19 |
2 to 11 m | 0.17−1.18 | 0.17−1.18 |
1 to <3 y | 0.19−0.42 | 0.19−0.42 |
3 to <5 y | 0.26−0.51 | 0.26−0.51 |
5 to <7 y | 0.30−0.59 | 0.30−0.59 |
7 to <9 y | 0.37−0.62 | 0.37−0.62 |
9 to <11 y | 0.39−0.70 | 0.39−0.70 |
11 to <13 y | 0.42−0.75 | 0.42−0.75 |
13 to <15 y | 0.49−0.90 | 0.49−0.90 |
≥15 y | 0.57−1.00 | 0.76−1.27 |
Footnotes
LOINC® Map
| Order Code | Order Code Name | Order Loinc | Result Code | Result Code Name | UofM | Result LOINC |
|---|---|---|---|---|---|---|
| 001370 | Creatinine | 2160-0 | 001370 | Creatinine | mg/dL | 2160-0 |
| 001370 | Creatinine | 2160-0 | 100779 | eGFR | mL/min/1.73 | 98979-8 |
| Order Code | 001370 | |||||
| Order Code Name | Creatinine | |||||
| Order Loinc | 2160-0 | |||||
| Result Code | 001370 | |||||
| Result Code Name | Creatinine | |||||
| UofM | mg/dL | |||||
| Result LOINC | 2160-0 | |||||
| Order Code | 001370 | |||||
| Order Code Name | Creatinine | |||||
| Order Loinc | 2160-0 | |||||
| Result Code | 100779 | |||||
| Result Code Name | eGFR | |||||
| UofM | mL/min/1.73 | |||||
| Result LOINC | 98979-8 |