Blood Tests for Renal Failure Evaluation

Core Laboratory Tests

The Kidney International recommends serum creatinine as the primary marker for kidney function assessment, which should be measured using a specific assay with calibration traceable to international standard reference materials 1
The Kidney International suggests that eGFR calculation should be derived from serum creatinine using the 2009 CKD-EPI equation rather than relying on serum creatinine concentration alone 1
Electrolytes, including sodium, potassium, calcium, chloride, phosphorus, and magnesium, should be assessed to evaluate electrolyte imbalances 3

The Annals of Internal Medicine recommends urine albumin-to-creatinine ratio (ACR) as the preferred method for assessing proteinuria from an untimed urine sample 2
The Kidney International suggests that urine sediment examination should be performed to detect abnormalities, including cells, casts, and crystals 1

The Kidney International recommends considering cystatin C as a confirmatory test when eGFR based on serum creatinine may be less accurate 1
The Kidney International suggests that the combined creatinine-cystatin C equation provides improved accuracy in certain populations 1

The Kidney International defines GFR categories, including G1 (≥90 ml/min/1.73m²), G2 (60-89 ml/min/1.73m²), G3a (45-59 ml/min/1.73m²), G3b (30-44 ml/min/1.73m²), G4 (15-29 ml/min/1.73m²), and G5 (<15 ml/min/1.73m²) 1

The Kidney International defines albuminuria categories, including A1 (<30 mg/g), A2 (30-300 mg/g), and A3 (>300 mg/g) 1

The Annals of Internal Medicine recommends annual screening with serum creatinine and urine albumin testing for patients with diabetes or hypertension 4
The National Kidney Foundation recommends assessing risk for CKD in all patients and performing blood pressure measurement, serum creatinine testing, urine albumin testing, and examination of urine for erythrocytes and leukocytes in those at increased risk 5
The Kidney International suggests that laboratory values should be monitored at intervals based on GFR category and albuminuria category to assess progression 3
The Kidney International recommends point-of-care testing for creatinine and urine albumin to facilitate earlier diagnosis in rural or remote locations 3

The Kidney International states that a single abnormal test result is insufficient for diagnosis of chronic kidney disease, and persistence of abnormalities for >3 months is required 1
The Kidney International notes that certain medications and substances can interfere with creatinine measurements, affecting eGFR accuracy 3
The Kidney International recommends standardized collection protocols for blood sample processing to ensure accurate results 3
The Journal of the National Comprehensive Cancer Network suggests that in patients with acute kidney injury superimposed on chronic kidney disease, interpreting blood test results requires comparison to baseline values 6
The Annals of Internal Medicine recommends confirmation with quantitative methods for proteinuria testing to avoid false-positive and false-negative results 2

The Kidney International recommends that monitoring frequency for patients with confirmed CKD should be guided by GFR category, albuminuria category, and rate of progression 3
The Kidney International suggests that more frequent monitoring is warranted for patients with rapidly declining kidney function or those at higher risk for progression 3