Semi-quantitative analysis of cerebrospinal fluid chemistry and cellularity using urinary reagent strip: An aid to rapid diagnosis of meningitis

Evaluation of the Effectiveness of Lumbar Punctures in Aneurysmal Subarachnoid Hemorrhage Patient with External Ventricular Drainage

BACKGROUND

For aSAH patients with external ventricular drainage (EVD) because of hydrocephalus, the consensus on application of CSF drainage from the lumbar cistern is mixed owing to concerns about its safety and questionable effectiveness. This study evaluated the additional effectiveness of CSF drainage from the lumbar cistern in aSAH patients with EVD.

METHODS

This was a retrospective and observational study of adult patients with aSAH who were admitted to the intensive care unit at the Wuhan Union Hospital between June 2018 and June 2019. Three aSAH patients with EVD and serial lumbar punctures (LPs) were selected for comparison of CSF components. Four more aSAH patients who underwent divergent CSF drainage were selected to profile the additional effectiveness of lumbar cistern drainage in aSAH patients with EVD.

RESULTS

Cases 1-3 with EVD and serial LPs showed dramatically higher red blood cell (RBC) and leukocyte counts with steeper changing curve in the lumbar cistern CSF than in the ventricle CSF. Case 5 had EVD alone and showed a slower clearing rate of blood clot in subarachnoid space compared with case 1. Case 4, with serial LPs alone, showed a steep changing curve of both RBC and leukocyte counts in the lumbar cistern CSF. Cases 6 and 7, with EVD and follow-up LPs, showed dramatically higher RBC and leukocyte counts in the lumbar cistern CSF than in the ventricle CSF after almost 2 weeks of EVD.

CONCLUSIONS

For aSAH patients with EVD, serial LPs can accelerate clearance of toxic products from the subarachnoid space.

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

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.

Utility of urine reagent strips in cerebrospinal fluid analysis: An aid to bedside diagnosis of meningitis

Context

The provision of initial treatment to a patient with suspected meningitis depends greatly on early recognition and rapid diagnostic evaluation of cerebrospinal fluid (CSF) leukocytes, proteins, and glucose. The diagnosis is time critical and timely intervention has an implication on the prognosis and outcome. Reasonably, sound laboratorial setups are not available in our country in the primary health-care level and, even in the settings where they are available, long waiting periods precede the availability of results.

Aims

We conducted this study to emphasize the role of urine reagent strip test as a rapid diagnostic tool in CSF analysis.

Settings and Design:

This is a prospective single-blinded study on 100 consecutive CSF samples received with in 1h of tap.

Subjects and Methods

All the 100 samples were subjected to definitive test being CSF microscopy and biochemical analysis of proteins and sugar and index test being a semi quantitative analysis of CSF leukocytes, proteins, and sugar by urinary reagent strips.

Statistical Analysis Used

The diagnostic accuracy of the reagent strip for different cutoff levels was estimated and tabulated in the form of sensitivity, specificity, positive predictive value, negative predictive value, and likelihood ratio.

Results

77% of cases were in the pediatric age group and 23% cases were adults. The sensitivity and specificity for leukocytes by the strip method for ≥15 cells/cumm were 89.28% and 98.61%, respectively, which increased to 100% with an increase in the counts. The reagent strip test had a sensitivity of 85.71% and a specificity of 95.65% for the protein levels >30 mg/dl which increased to 100% with an increase in protein levels. The reagent strip test for glucose was highly specific (100%) but less sensitive.

Conclusions

The results indicate that urine reagent strip is instrumental in bedside CSF analysis and has a future stand in the diagnosis of meningitis.

Reagent Strips as an Aid to Diagnosis of Neonatal Meningitis in a Resource-limited Setting

BACKGROUND

Without early recognition and treatment, neonatal meningitis (NM) has a high mortality and morbidity. Although some neonates have features of NM, many do not. In many low-resource settings, the laboratory support to diagnose NM is not available, and bedside diagnostics are needed.

METHODS

This retrospective study was conducted in a neonatal unit in Uganda. Clear cerebrospinal fluid samples were routinely screened for glucose, protein and leukocytes on a Combur®-10 urinalysis reagent strip. A definitive diagnosis was made using laboratory analysis. The results of the screening and definitive tests were compared.

RESULTS

The reagent strip showed moderate sensitivity and high specificity for leukocytes ≥10×106 cells/l, high sensitivity for protein ≥100 mg/dl and high specificity for glucose <50 mg/dl.

CONCLUSION

The use of reagent strips has the potential to improve and hasten the diagnosis of probable NM in settings where adequate or timely laboratory support is not available.

Utility of the urine reagent strip leucocyte esterase assay for the diagnosis of meningitis in resource-limited settings: meta-analysis

OBJECTIVE

Diagnosis of bacterial meningitis often requires cytometry, chemistry and/or microbiologic culture capabilities. Unfortunately, laboratory resources in low-resource settings (LRS) often lack the capacity to perform these studies. We sought to determine whether the presence of white blood cells in CSF detected by commercially available urine reagent strips could aid in the diagnosis of bacterial meningitis.

METHODS

We searched PubMed for studies published between 1980 and 2016 that investigated the use of urine reagent strips to identify cerebrospinal fluid (CSF) pleocytosis. We assessed studies in any language that enrolled subjects who underwent lumbar puncture and had cerebrospinal fluid testing by both standard laboratory assays and urine reagent strips. We abstracted true-positive, false-negative, false-positive and true-negative counts for each study using a diagnostic threshold of ≥10 white blood cells per microlitre for suspected bacterial meningitis and performed mixed regression modelling with random effects to estimate pooled diagnostic accuracy across studies.

RESULTS

Our search returned 13 studies including 2235 participants. Urine reagent strips detected CSF pleocytosis with a pooled sensitivity of 92% (95% CI: 84-96), a pooled specificity of 98% (95% CI: 94-99) and a negative predictive value of 99% when the bacterial meningitis prevalence is 10%.

CONCLUSIONS

Urine reagent strips could provide a rapid and accurate tool to detect CSF pleocytosis, which, if negative, can be used to exclude diagnosis of bacterial meningitis in settings without laboratory infrastructure. Further investigation of the diagnostic value of using protein, glucose and bacteria components of these strips is warranted.

Biochemical analysis of cerebrospinal fluid in the laboratories of deployed medical treatment facilities: are Multistix 10 SG strip and iSTAT useful?

INTRODUCTION

During military deployment, the diagnosis and the management of acute bacterial meningitis can be problematic, as deployed Medical Treatment Facilities (MTFs) often have a limited laboratory diagnostic capability. However, French Role 2 and 3 MTFs have point-of-care (POC) testing to perform urinary (Multistix 10 SG strip) and blood (iSTAT handheld analyser) biochemical testing mentioned in AMedP8.5. The purpose of this study was to compare the accuracy of this urine test strip and of the iSTAT CHEM8 and CG4 cartridges with a standard hospital bench top analyser in order to determine if these POC devices have a potential role in the biochemical analysis of cerebrospinal fluid (CSF protein, CSF glucose and CSF lactate, respectively).

METHODS

Agreement between the index methods and the reference methods (suitable kits on the Cobas 6 000 System) was evaluated by parallel testing of 30 CSF samples by both techniques. For CSF protein, agreement between the strip and the reference method was evaluated determining the κ coefficient. For CSF glucose and CSF lactate subgroups, least squares linear regressions were calculated and Bland-Altman analyses were performed.

RESULTS

The Multistix 10 SG strip can be used to make a semiquantitative determination of CSF protein. A good agreement between the strip and the reference method was observed (κ coefficient: 0.93 (IC₉₅ 0.82 to 1)). This strip is thus well adapted to demonstrate an elevation of CSF protein level as observed in acute bacterial meningitis. The iSTAT CHEM8 and CG4+ cartridges correlated well with the reference methods for the determination of CSF glucose and CSF lactate, respectively (r²>0.98) but exhibited a negative bias (∼ -7% and ∼ -15%, respectively).

CONCLUSIONS

The combined use of the Multistix 10 SG strip and of the iSTAT system appears to be an attractive solution for the biochemical investigation of CSF in medical treatment facilities with limited laboratory diagnostic capability.