Role of Platelets to Lymphocytes Ratio and Neutrophils to Lymphocytes Ratio in Detection of Acute Kidney Injury in Intensive Care Unit Patients

Intensive Care Unit (ICU)-acquired acute kidney injury (AKI) is a frequent consequence with many risk factors. When AKI develops, inflammatory mediators are a key factor. The ratios of neutrophils to lymphocytes (NLR) and platelets to lymphocytes (PLR) have been linked in many studies to the incidence of AKI. Our goal was to determine whether the PLR and the NLR might be used as a simple method for detecting acute kidney injury in ICU patients. 80 critically ill patients were included in our cross-sectional study, recruited from AL-Zahraa University Hospital. Their age ranged from 18 to 60 years for both sexes with in less than 6 hours from ICU admission with normal serum creatinine on admission. The following were done for the patients: a detailed medical history, complete examination, routine laboratory investigation including serum creatinine on admission then daily during ICU stay and estimation of GFR, using MDRD formula, complete blood count (CBC) daily follow up (to calculate PLR and NLR), fasting lipid profile, FBS, liver function tests, ESR, CRP, measurement of 24hr UOP, Na, K and ABG. On comparison of the AKI group to the non-AKI group, there was a highly significant rise in PLR and NLR at admission. However, NLR and PLR did not significantly rise 48 hours after admission. NLR was excellent (AUC= 0.940) in discriminating patients with AKI from patients without AKI at cut off value of >2.5 with sensitivity (83.6%), specificity (96%), PPV (97.9%), NPV (72.7%) and P-value (<0.001). PLR was good (AUC= 0.744) in discriminating patients with AKI from patients without AKI at cut off value of >134.8 with sensitivity (63.6%), specificity (96%), PPV (97.2%), NPV (54.5%) and P-value (<0.001).  AKI in the ICU has been correlated with increased morbidity and mortality, so early detection is essential. NLR and PLR are both useful early indicators for the diagnosis of AKI.