Table 3. Sources of errors in GFR estimation using creatinine.
Source of error | Example | Actions |
---|---|---|
Non-controllable variations | ||
Non-steady state | AKI | Laboratory professionals and clinicians should be aware of listed limitations. For a better flow of information please consult the Appendix 2. |
Factors affecting creatinine generation | Race Extremes in muscle mass (body building, anorexia) Diet/nutrition (high protein diet, creatine supplements, creatine, vegetarians) Muscle wasting diseases (muscular dystrophy, rhabdomyolysis) Ingestion of cooked meat |
|
Factors affecting tubular secretion of creatinine | Decrease by drug-induced inhibition (cimetidine, fenofibrate) Dialysis |
|
Factors affecting extra-renal elimination of creatinine | Decrease by gut creatininase by antibiotics Increased by large volume losses of extracellular fluid |
|
Higher GFR | Higher measurement error at low serum creatinine concentrations | |
Partly-controllable variations | ||
Interferences with creatinine assay | Spectral interference (e.g. bilirubin, some drugs) Chemical interference (e.g. glucose, ketones, bilirubin, some drugs) Lipemia (serum delipidation with heparin and MgCl2 may cause falsely decreased creatinine concentration) |
For obtaining an adequate blood sample laboratory professionals should implement the valid national recommendations for venous and capillary blood sampling (References: 11, 12) For management of lipemic samples please consult a review by Nikolac et al. (Reference: 25) Regarding analytical interferences, laboratory professionals should verify the data declared by the manufacturer and define their own acceptability criteria. |
AKI - acute kidney injury. GFR - glomerular filtration rate. (Reproduced with permission from KDIGO 2012 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease. Kidney Int, Suppl 2013;3:1-150.) |