Calcre

CALCRE is intended for healthcare professionals who use various methods to measure serum creatinine and allows the results to be converted to a manageable IDMS method. It also allows calculating the glomerular filtration rate (eGFR) using the four most used equations according to age and classifying patients according to the stage of Chronic Kidney Disease they present.

Creatinine is a final product of muscle metabolism, eliminated from the body basically by glomerular filtration. Its serum concentrations have an inverse and hyperbolic relationship with the glomerular filtration rate, which is considered the best marker of renal function. Thus, the most widely used method to calculate the estimated glomerular filtration rate (eGFR) are the equations that predict it from serum creatinine concentrations. Serum creatinine measurements in clinical practice are usually done by the Jaffé reaction with alkaline picrate (by the kinetic method or end point) or by the enzymatic method.

Reference methods such as gas and liquid chromatography coupled with isotope dilution mass spectrophotometry (IDMS) are not in routine use. In 2002, the K/DOQI guidelines appeared, unifying the criteria for the diagnosis and classification of CKD, based on the (eGFR) and the presence of markers of kidney damage. This document also recommends that laboratories report eGFR and categorize subjects by CKD stage according to the recommended classification.

As this was implemented, the great variability of the eGFR of the patients became evident based on the measurement method used for serum creatinine. As a consequence of this, a consensus document of the National Renal Education Program of the USA (NKDEP) and the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) was developed in 2006, in which they recommend recalibrating the measurement methods of serum creatinine to be traceable to a reference method (IDMS) or use enzymatic methods, thus minimizing bias between methods and laboratories.

Most creatinine measurements are made by the Jaffé kinetic method (alkaline picrate), either automatically or manually, without IDMS correction. The enzymatic method, which is 10 times more expensive, has very limited availability. Furthermore, laboratories do not routinely report eGFR and classification of patients by CKD stage. Faced with this situation, equations have been developed that allow serum creatinine concentrations measured by the Jaffé kinetic method to be corrected, either automatically or manually, against a traceable IDMS method, which is known as the compensated Jaffé kinetic method.

However, there is no tool that allows for automatic correction of serum creatinine according to the measurement method used, and eGFR calculations using the equations recommended by international guidelines, as well as classifying patients by stages of CKD. In response to this problem, this work is developed with the aim of presenting a computer application that corrects serum creatinine to a traceable IDMS method (compensated Jaffé), calculates the eGFR according to user preferences (within the recommended equations) and classifies the patient. subject by CKD stage, automatically.