Reagent strips test: A simplified method for prompt analysis of cerebrospinal fluid in neurological disorders in emergency

Abstract

Introduction: The initial examination of cerebrospinal fluid (CSF) for proteins, glucose, and leukocytes, is still the gold standard investigation in some neurological conditions like meningitis. Aims and objective of the present study were to determine the accuracy of urinary reagent strip for semi-quantitative analysis of protein, glucose, leucocytes and erythrocytes in CSF along with its role in emergency for rapid diagnosis of neurological conditions.

Materials and methods: 360 samples of CSF were received in emergency laboratory of a tertiary care hospital in a period of 6 months. All CSF samples were subjected to two types of tests-the definitive test and the index test. CSF microscopy for leucocyte and erythrocyte as well as biochemistry tests for protein and glucose on automated biochemistry analyser were considered as definitive test. The index test for protein, glucose, leucocyte and erythrocyte for the same sample was conducted by Combur-10 urinary reagent strip.

Result: The strip test showed a sensitivity of 99% and a specificity of 54% for proteins. With respect to glucose, the strip was highly sensitive (98%) as well as highly specific (92%).It showed a high sensitivity and specificity for leukocytes ≥ 10 cells/cumm i.e.100% and 96% respectively. For CSF erythrocytes sensitivity and specificity was 100.

Conclusion: Urinary reagent strip can be used routinely for rapid analysis of CSF. If implemented, this technique will be useful especially in emergency settings as well as in areas with limited resources.

Keywords: Accuracy; Cerebrospinal fluid analysis; Emergency setting; Semi-quantitative; Urinary reagent strips.

Fig. 1

Showing color chart scale as shown on the label of combur-10urinary reagent strip.

Fig. 2

Box & whisker plot showing the distribution of reference standard values for each strip color, (a) leucocytes, (b) proteins, (c) glucose and (d) erythrocyte. Horizontal line, box, whisker and dots indicate median (50^th centile), 25th and 75th centile, ranges and outliers respectively.

Fig. 3

Receiver operator curves (ROC curve)for performance of reagent strips along with area under the curve (AUC), (a) leucocytes, (b) proteins, and (c) glucose and (d) erythrocytes.

Fig. 4

Spectrum of neurological disorders studied.