# Observational quality control study: insourcing multi-PCR-impact on the use of anti-infectives for patients with pleocytosis

## TL;DR

This study shows that insourcing specific tests for CNS infections reduces hospital stays and antibiotic use, despite higher testing costs.

## Contribution

The study evaluates the impact of insourcing ME-PCR, CXCL 13, and AI tests on diagnostic efficiency and treatment in CNS infections.

## Key findings

- Insourcing tests significantly reduced hospital stay and anti-infective exposure.
- Diagnostic time for CNS diseases decreased from 13.6 to 9.7 days on average.
- Higher testing costs were offset by increased patient throughput and economic benefits.

## Abstract

An analysis of the cerebrospinal fluid (CSF) is essential for diagnosis of meningitis, headache, disturbance of conscience, cranial nerves or autoimmune-related conditions of the CNS. The initial treatment of pleocytosis usually consists of both antiviral therapy and antibiotics until laboratory results enable a more specific approach. Therefore, it is crucial to rapidly and accurately detect pathogens.

In this observatory, monocentric study of quality management data, we studied insourcing of ME-PCR, CXCL 13, Antibody-specific Index (AI) for HSV, VZV (G\documentclass[12pt]{minimal}
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\begin{document}$$_{1}$$\end{document}1) compared with outsourced laboratory measurements (G\documentclass[12pt]{minimal}
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\begin{document}$$_{0}$$\end{document}0) and its benefit for the work-up. Before the implementation of these parameters, data from 150 patients were sampled, followed by 210 after the introduction of ME-PCR, CXCL 13 and AI. Data were collected, anonymized, and analysed afterwards. All were treated in hospital for suspected infections of the Central Nervous System (CNS). The length of hospital stay (LOS), intervals from lumbar puncture, the cumulative dose of anti-infective agents, length of treatment and the potential impact on patients’ safety parameters were examined.

The G\documentclass[12pt]{minimal}
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\begin{document}$$_{1}$$\end{document}1-group showed a significant decrease of LOS (p<0.001), exposure to antiviral, and antibiotic agents decreased significantly (p < 0.001, each). Insourcing of ME-PCR and CXCL 13 shortened the time-span from admission to diagnosis in patients with suspected inflammatory CNS disease from 13.6 (6.6) to 9.7 (6.7) days in mean (SD).

The shortened average LOS after changing the diagnostic pathway increased direct costs for test kits. However, these costs were by far outweighed the economical benefit of being able to treat more patients in the same time. This analysis should be replicated in a different Medical Care System than the one in which this analysis has been calculated.