Diagnostic value of bedside tests (urine reagent strips and semi-quantitative procalcitonin (PCT-Q)) in the diagnosis of acute bacterial meningitis in Egyptian patients

Bacterial meningitis is a serious infection of the central nervous system. On the other hand, aseptic meningitis is a benign self-limited disease. Differentiating both diseases is of great importance. Earlier studies using urine reagent strips and procalcitonin (PCT) for diagnosis of meningitis had given a high sensitivity and specificity rates reaching 100%. The main aim of this study was to evaluate the usefulness of two bedside diagnostic tests in the diagnosis of meningitis. These were urine reagent strips and semi-quantitative procalcitonin (PCT-Q) test. One hundred patients with clinical and laboratory data suggesting of meningitis were included in this study. Complete biological and biochemical laboratory examination of cerebrospinal fluid (CSF), and serum inflammatory markers were done. According to this work, the 100 patients were classified into 64 patients with bacterial meningitis and 36 patients with aseptic meningitis. The CSF samples were tested using urine reagent strips for protein, glucose and leukocytes; as well as for PCT-Q test to detect its ability in differentiating bacterial from viral aseptic meningitis. Positive bacterial culture is the gold standard in the diagnosis of bacterial meningitis but it yielded a very low positivity rate (combined Gram stain and cultures were positive in only 4%). Although CSF protein concentration and leukocyte count and serum CRP were significantly higher in bacterial than aseptic meningitis, there was a wide area of overlapping results between the two groups. The number of reagent strip results coinciding with the laboratory results was 72%, 64% and 48% for leukocytes, protein and glucose respectively. Sensitivity rates were moderate and the degree of agreement between CSF strip and laboratory results were increased with higher grades for leukocytosis. PCT-Q had a good discriminating ability in differentiating bacterial from viral meningitis. With a cutoff value of 0.5 ng/dL, it was positive in 87% of patients with bacterial meningitis and negative in 91% of cases of viral aseptic meningitis. The use of reagent strips for the diagnosis of meningitis can be used only as a preliminary screening test till the laboratory results became available. PCT-Q test was more sensitive in differentiating bacterial from viral meningitis but it cannot be used alone for this diagnosis.