Laboratory diagnostics of chronic kidney disease in Croatia: state of the art

How well do Croatian laboratories adhere to national recommendations for laboratory diagnostics of chronic kidney disease (CKD)?

Background

In 2014, the Joint Croatian Working Group (JCWG) for laboratory diagnostic of chronic kidney disease (CKD) conducted a survey across medical-biochemistry laboratories which demonstrated a large heterogeneity in this area of laboratory medicine. To ensure the tools for the standardization process, in 2017 the JCWG-CKD published the first Croatian recommendations for laboratory diagnostics of CKD. To assess the implementation process, we have repeated a survey to explore how well laboratories adhere to the recommendations.

Methods

An invitation to the survey was sent to all Croatian medical-biochemistry laboratories (n = 196). The questionnaire was designed in a form of 19 questions and statements, with possible multiple answers.

Results

The response rate was 98/196 (50.0%). The predominant method for serum creatinine measurement was the standardized compensated Jaffe method (79.2%). There was substantial decrease in the number of laboratories which measure creatinine with the non-standardized uncompensated Jaffe method, compared with the initial 2014 assessment; 7% vs. 40%, respectively. The number of the laboratories that did not report estimated glomerular filtration rate (eGFR) values decreased almost by half compared to the initial data (37.6% vs. 74.4%). However, compared to the 2014 initial assessment, a similar number of laboratories (54/98 vs. 58/80) did not measure urine albumin or protein.

Conclusions

The collected data showed a substantial improvement in the standardization of the serum creatinine measurement, as well as in the reporting of eGFR. However, albuminuria or proteinuria assessment is still not implemented nationwide, mainly in primary health care laboratories. This demonstrates the importance of promoting and monitoring implementation of guidelines after publication.

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

Introduction

The aim of the study is to assess the degree of adherence of medical laboratories to Kidney Disease Improving Global Outcomes (KDIGO) 2012 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease (CKD) in laboratory practice in Czechia and Slovakia.

Materials and methods

An electronic questionnaire on adherence to KDIGO 2012 guideline was designed by an external quality assessment (EQA) provider SEKK spol. s.r.o. The questionnaire was placed and distributed through website to all medical biochemistry laboratories in Czechia and Slovakia (N = 396).

Results

A total of 212 out of 396 laboratories responded to the questions, though some laboratories only answered some questions, those applicable to their practice. A total of 48 out of 212 laboratories adopted the KDIGO 2012 guideline in full extent. The metrological traceability of creatinine measurement to standard reference material of SRM 967 was declared by 180 out of 210 laboratories (two of the responding laboratories did not measure creatinine). Thirty laboratories are not well educated on traceability of creatinine measurement and seven laboratories do not calculate estimated glomerular filtration rate (eGFR). Both urinary albumin concentration and albumin to creatinine ratio are reported by 144 out of 175 laboratories (37 of the responding laboratories did not measure urinary albumin).

Conclusion

Majority of laboratories in Czechia and Slovakia adopted some parts of the KDIGO 2012 guideline in their practice, but only 23% of the laboratories apply them completely. Thus, further education and action should be conducted to improve its implementation.

Developing Paper Based Diagnostic Technique to Detect Uric Acid in Urine

Urinary or serum uric acid concentration is an indicator of chronic kidney condition. An increase in uric acid concentration may indicate renal dysfunction. Reliable instantaneous detection of uric acid without requiring sophisticated laboratory and analytical instrumentation, such as: chromatographic and spectrophotometric methods, would be invaluable for patients with renal complication. This paper reports the early development of a simple, low-cost, instantaneous and user-friendly paper based diagnostic device (PAD) for the qualitative and quantitative detection of uric acid in urine. A colorimetric detection technique was developed based on the intensity of Prussian blue color formation on paper in presence of uric acid; the reaction rate of corresponding chemical reactions on paper surface was also studied. Based on the colorimetric signal produced on paper surface, a calibration curve was developed to detect unknown concentration of uric acid in urine. The effect of temperature on formation of color signal on paper surface was also analyzed. In this study, estimation of urinary uric acid using MATLAB coding on a windows platform was demonstrated as the use of software application and digital diagnostics. This paper-based technique is faster and less expensive compared to traditional detection techniques. The paper-based diagnostic can be integrated with a camera of smart phone, tablet computer or laptop and an image processing application (using windows/android/IOS platform) as a part of digital diagnostics. Therefore, with proper calibration, the paper-based technique can be compatible and economical to the sophisticated detection techniques used to detect urinary uric acid.

Task Force on CKD - We have Come a Long Way

Chronic Kidney Disease (CKD) is an important medical condition where diagnosis, staging and monitoring is largely based on routine laboratory tests. During the last 15 years there have been many important changes in the clinical management of CKD described in key international guidelines. In order to successfully implement these guidelines, laboratories must collaborate with clinicians to provide a co-ordinated service, including accurate measurements and of creatinine and urine albumin and reporting of an estimated glomerular filtration rate (eGFR). The IFCC/WASPaLM Task Force on Chronic Kidney Disease (TF-CKD) was established in 2008 and since that time has worked to improve laboratory testing in CKD. Key aspects of the work of the TF-CKD include supporting national laboratory medicine organisations to develop CKD testing guidelines, recognition of the vital role of collaboration between laboratory and clinical organisations, the importance of accurate measurements, and endorsement of the KDIGO 2012 CKD guidelines. A key function of the TF-CKD has been to facilitate sharing and learning between countries to provide the best outcomes.

A Pathway to National Guidelines for Laboratory Diagnostics of Chronic Kidney Disease - Examples from Diverse European Countries

The principal benefit of guidelines is to improve the quality of care received by patients. In the 2012 Clinical Practice Guideline for the Evaluation and Management of Chronic Kidney Disease (KDIGO) was released and it is designed to provide information and assist decision making. This review gives a brief overview of a various national CKD guidelines that rely on the newly released KDIGO guidelines. All of the included countries (France, Turkey, Norway and Croatia) are non-English speaking countries and they differ in population and socio economic aspects. Examples shown in this review may provide valuable experience for countries that are in process of creating their national CKD guidelines.

Impact of creatinine methodology on glomerular filtration rate estimation in diabetes

AIM

To evaluate the influence of creatinine methodology on the performance of chronic kidney disease (CKD)-Epidemiology Collaboration Group-calculated estimated glomerular filtration rate (CKD-EPI-eGFR) for CKD diagnosis/staging in a large cohort of diabetic patients.

METHODS

Fasting blood samples were taken from diabetic patients attending our clinic for their regular annual examination, including laboratory measurement of serum creatinine and eGFR.

RESULTS

Our results indicated an overall excellent agreement in CKD staging (kappa = 0.918) between the Jaffé serum creatinine- and enzymatic serum creatinine-based CKD-EPI-eGFR, with 9% of discordant cases. As compared to the enzymatic creatinine, the majority of discordances (8%) were positive, i.e., associated with the more advanced CKD stage re-classification, whereas only 1% of cases were negatively discordant if Jaffé creatinine was used for eGFR calculation. A minor proportion of the discordant cases (3.5%) were re-classified into clinically relevant CKD stage indicating mildly to moderately decreased kidney function (< 60 mL/min per 1.73 m²). Significant acute and chronic hyperglycaemia, assessed as plasma glucose and HbA_1c levels far above the recommended glycaemic goals, was associated with positively discordant cases. Due to a very low frequency, positive discordance is not likely to present a great burden for the health-care providers, while intensified medical care may actually be beneficial for the small number of discordant patients. On the other hand, a very low proportion of negatively discordant cases (1%) at the 60 mL/min per 1.73 m² eGFR level indicate a negligible possibility to miss the CKD diagnosis, which could be the most prominent clinical problem affecting patient care, considering high risk of CKD for adverse patient outcomes.

CONCLUSION

This study indicate that compensated Jaffé creatinine procedure, in spite of the glucose-dependent bias, is not inferior to enzymatic creatinine in CKD diagnosis/staging and therefore may provide a reliable and cost-effective tool for the renal function assessment in diabetic patients.

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

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.

Is peritoneal dialysis causing a measurable burden of inflammatory and endothelial injury on top of metabolic syndrome?

PURPOSE

Low-grade chronic inflammation is present in patients on peritoneal dialysis (PD) and in metabolic syndrome (MS). Due to possible greater endothelial changes in dialyzed patients, inflammatory response and oxidative stress are probably stronger in patients on PD. The objective of the study was to investigate possible in between adipokines, inflammatory, endothelial and oxidative stress markers between MS patients and patients on PD.

METHODS

Concentrations of adipokines (leptin, resistin), inflammatory markers [interleukin-6 (IL-6), soluble tumor necrosis factor alpha receptor (sTNF-R), myeloperoxidase (MPO), monocyte chemoattractant protein 1 (MCP-1)] and endothelial markers [soluble intracellular adhesion molecule-1 (sICAM-1), soluble CD40 ligand (sCD40L)] were determined in 55 MS patients and 18 patients on PD, with flow cytometry, and visfatin concentration was measured with ELISA. Routine biochemistry parameters were measured on Beckman Coulter AU2700 analyzer.

RESULTS

Patients on PD have significantly higher concentration of: CRP [6.5 (3.7-12.1) versus 2.6 (1.3-4.0) mg/L, P < 0.001], IL-6 [13.83 (8.48-31.31) versus 2.05 (0.67-4.11) pg/mL, P < 0.001], MCP-1 [2172.28 (1563.84-2922.77) versus 1353.58 (1166.33-1961.70) pg/mL, P = 0.023], sTNF-R [18.25 (12.81-25.22) versus 1.23 (0.89-1.43) ng/mL, P < 0.001] and sICAM-1 [830.03 (599.21-967.02) versus 463.85 (315.25-751.71) ng/mL, P = 0.006] than subjects with MS. MS patients have higher concentrations of MPO [175.47 (120.15-231.67) versus 101.76 (53.55-186.06) ng/mL, P = 0.016] and visfatin [1.5 (0.9-2.3) versus 0.9 (0.6-1.6) ng/mL, P = 0.013].

CONCLUSION

In patients on PD, inflammatory reaction is higher than in patients with MS. On the contrary, patients with MS have stronger oxidative stress response and adipose tissue activity caused probably by the chronic low level of inflammation and underlying metabolic disorders.