[Assessment of kidney function : Creatinine is not the whole story]

Area of Science:

• Nephrology
• Clinical Chemistry

Background:

• Chronic renal insufficiency (CRI) significantly impacts quality of life and increases mortality, primarily from cardiovascular complications.
• Early-stage CRI is frequently underestimated due to normal serum creatinine levels influenced by endogenous factors like age and muscle mass.
• Accurate measurement of glomerular filtration rate (GFR) is crucial for timely therapeutic intervention.

Purpose of the Study:

• To review current methods for assessing kidney function in routine clinical practice.
• To highlight the importance of accurate GFR estimation for early detection and management of chronic kidney disease (CKD).
• To discuss the utility and limitations of urinalysis as a screening tool.

Main Methods:

• Review of established and emerging methods for GFR estimation.
• Evaluation of the accuracy and practicality of creatinine clearance and calculation algorithms.
• Assessment of urinalysis techniques, including dipstick tests and urinary microscopy.

Main Results:

• Serum creatinine can be misleading in early CRI.
• Radionuclide techniques and 24-h urine collection for creatinine clearance are cumbersome and error-prone for routine use.
• The CKD-EPI formula is the most accurate method for GFR estimation in routine clinical practice.
• Urinalysis offers simple, economic screening but requires careful interpretation due to limitations.

Conclusions:

• The CKD-EPI formula should be utilized for screening and continuous surveillance of kidney function.
• Urinalysis serves as a valuable, non-invasive screening tool when diagnostic limitations are considered.
• Accurate GFR assessment is vital for managing CRI and preventing cardiovascular complications.