# Is synovial calprotectin lateral flow test a reliable intraoperative biomarker for periprosthetic joint infection? A systematic review and meta-analysis

## TL;DR

This study evaluates the synovial calprotectin lateral flow test as a reliable intraoperative tool for diagnosing joint infections during surgery.

## Contribution

The study provides a meta-analysis of synovial calprotectin LFT's diagnostic accuracy for PJI, highlighting its potential as a real-time surgical aid.

## Key findings

- Synovial calprotectin LFT showed 88% sensitivity and 89% specificity for detecting periprosthetic joint infection.
- A cutoff of ≥ 50 mg/L improved diagnostic performance across all metrics.
- The test has an area under the curve of 0.94, indicating strong diagnostic accuracy.

## Abstract

Periprosthetic Joint Infection (PJI) remains one of the most challenging complications in arthroplasty, often leading to diagnostic uncertainty and suboptimal treatment decisions. Synovial calprotectin has emerged as a promising biomarker, with the lateral flow test (LFT) offering real-time results for intraoperative decision-making. This meta-analysis aimed to evaluate the diagnostic accuracy of intraoperative synovial calprotectin LFT in detecting PJI.

A systematic review and meta-analysis were conducted according to PRISMA guidelines. Thirteen studies comprising 990 patients were included. Pooled sensitivity, specificity, positive and negative predictive values (PPV, NPV), likelihood ratios (LR+, LR−), diagnostic odds ratio (DOR), and area under the curve (AUC) were calculated using a random-effects model. Subgroup analyses were performed based on test kit type and calprotectin cutoff values.

The pooled sensitivity and specificity of synovial calprotectin LFT were 88% (95% CI: 82–92%) and 89% (95% CI: 83–93%), respectively, with an AUC of 0.94. The DOR was 56.1 (95% CI: 28.4-110.8). The ≥ 50 mg/L cutoff subgroup demonstrated superior diagnostic performance across all metrics. Despite subgroup analysis, heterogeneity remained high (I² = 74.1%), likely due to differences in reference standards, joint types, and study design.

Intraoperative synovial calprotectin LFT is a highly accurate and rapid diagnostic tool for PJI, with strong applicability in real-world surgical settings. Its cost-effectiveness and ease of use support its integration as a valuable adjunctive marker within standard diagnostic algorithms, providing supplementary evidence when conventional criteria remain inconclusive.