The role of laboratory testing in detection and classification of chronic kidney disease: national recommendations

Abstract

Chronic kidney disease (CKD) is a common clinical condition with significant adverse consequences for the patient and it is recognized as a significant public health problem. The role of laboratory medicine in diagnosis and management of CKD is of great importance: the diagnosis and staging are based on estimation of glomerular filtration rate (eGFR) and assessment of albuminuria (or proteinuria). Therefore, the joint working group of the Croatian society of medical biochemistry and laboratory medicine and Croatian chamber of medical biochemists for laboratory diagnostics in CKD issued this national recommendation regarding laboratory diagnostics of CKD. Key factors for laboratories implementing the national guidelines for the diagnosis and management of CKD are: 1. Ensure good communication between laboratory professionals and clinicians, such as nephrologists or specialists in general/family medicine, 2. Ensure all patients are provided with the same availability of laboratory diagnostics, 3. Ensure creatinine assays are traceable to isotope dilution mass spectrometry (IDMS) method and have minimal bias and acceptable imprecision, 4. Select the appropriate GFR estimating formula. Recommended equation is the 2009 Chronic Kidney Disease Epidemiology Collaboration (CKD – EPI) equation, 5. In reporting the key laboratory tests (creatinine, eGFR, urine albumin-to-creatinine ratio, urine protein-to-creatinine ratio) use the appropriate reporting units, 6. Provide adequate information on limitations of creatinine measurement. The manuscript has been organized to identify critical points in laboratory tests used in basic laboratory diagnostics of CKD and is based on the Kidney Disease: Improving Global Outcomes (KDIGO) 2012 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease.

Assessment of the degree of adherence of medical laboratories to KDIGO 2012 guideline for evaluation and management of CKD in Czechia and Slovakia

“…Biljak et al reported 6 key factors for laboratories implementing the national guidelines for the diagnosis and management of CKD. The first factor is good communication between laboratory and clinicians ( 22 ). We also share the opinion that open and frequent communication is important for any guideline implementation.…”

Laboratory testing of extravascular body fluids

“…Test reports should include the test result and the type of fluid analysed ( 5 , 10 ). Laboratories should provide clinical decision limits and interpretive information with each pleural fluid test result to guide clinical interpretation and decision-making (Table 3 and Appendix 2) (Class 1) ( 2 , 5 , 18 , 23 ).…”

The Linearity Problem of Protein Measurement and Hook Effect in Albumin Measurement in Body Fluids

“…The linearity problem of protein measurement and hook effect in albumin measurement from body fluids S erum total protein (sPRT) and serum albumin (sALB) tests and micro total protein (MTP) and micro albumin (MA) tests for various body fluids are routinely performed in clinical biochemistry laboratories. These analyses are crucial for screening kidney pathologies from urine samples and for their diagnosis, prognosis, and treatment planning [1]; for differentiating exudate and transudate from pleural fluids [2]; and for investigating central nervous system infections and assessing blood-brain barrier functions from the cerebrospinal fluid (CSF) [3]. Levels of sPRT and sALB are high enough to be expressed in grams, and they vary in a certain range.…”