LES INTERFERENCES ANALTIQUES EN ANALYSES BIOCHIMIQUES AU NIVEAU DU CHU DE MOSTAGANEM

Abstract

Biochemical analyses are crucial in medical patient management, enabling health status assessment, early detection of certain pathologies, and guiding therapeutic decisions. The reliability and accuracy of laboratory results are paramount for ensuring the quality of diagnoses and follow-up care. Analytical interferences are a major source of errors in medical laboratories, with the most studied interfering substances being haemolysis, jaundice, lipemia, and drug interferences. To study these interferences, blood samples were collected and transported to the central laboratory. Enzymatic assays of blood urea, creatinine, blood ionogram, HbA1c, and bilirubin were performed using reagents based on methods such as Jaffé and HPLC. In cases of red blood cell haemolysis, intracellular Na+ and K+ are released into the serum, falsely increasing the levels of these ions in the blood ionogram. Our results showed a positive correlation between haemolysis and sodium levels (0.174688), a positive correlation between haemolysis and potassium levels (0.326950), and a correlation between haemolysis and Cl- levels of 0.063054. In individuals with renal insufficiency, an increase in blood urea is observed, which is converted into ammonia and then into ISO citrate, resulting in increased HbA1c levels. There is a positive correlation between urea and glycated haemoglobin in both women and men (0.42751862715702776), a positive correlation between urea and age in both women and men (0.4113836510789007), and a negative correlation between glycated haemoglobin in women and men (-0.164793993034). In Jaffe reaction-based automates, bilirubin is oxidized by the alkaline reagent into biliverdin, especially at the beginning of the reaction, decreasing absorbance at 510 nm (the wavelength where bilirubin absorbance is maximal) and increasing absorbance at 620 nm (the wavelength where biliverdin absorbance is maximal). If creatinine measurement is performed initially in the presence of bilirubin, the absorbance around 510 nm will be decreased due to the presence of bilirubin, resulting in falsely decreased creatinine levels. Gardénal is an enzymatic indicator that increases renal assessment, and our results showed a positive correlation between bilirubin and creatinine in women (0.240474) and a negative correlation in men (-0.15680). To avoid these interferences, it is crucial to have an in-depth understanding of the different types of interferences, optimize analytical procedures, maintain close communication with clinicians, and implement protocols for detecting and managing interferences, while continuously monitoring scientific advancements in this field.