Synovial fluid neutrophil gelatinase-associated lipocalin can be used to accurately diagnose prosthetic joint infection.

OBJECTIVES

Neutrophil gelatinase-associated lipocalin (NGAL) in synovial fluid (SF) may have potential diagnostic value for prosthetic joint infection (PJI). This study aimed to study (i) the diagnostic performance of SF-NGAL levels for diagnosing PJI and (ii) the impact of previous antibiotic use on the SF-NGAL levels.

METHODS

Consecutive patients who needed hip or knee revision surgery were included prospectively from January 2017 to September 2018. The patients were divided into the PJI group and the aseptic failure group. An enzyme-linked immunosorbent assay was used to determine the SF-NGAL level.

RESULTS

A total of 50 of 78 included patients were diagnosed with PJI. The median SF-NGAL level was 3633 ng/ml (interquartile range [IQR], 1332-10,737) in the PJI group and 26.8 ng/ml (IQR, 12.4-52.5) in the aseptic failure group (P <0.0001). When the SF-NGAL threshold was 263 ng/ml, the area under the curve was 0.98, the sensitivity was 92.9%, and the specificity was 98%. The median level was 5779 ng/ml (IQR, 1425-13,072) in the antibiotic group and 2590 ng/ml (IQR, 932-8970) in the nonantibiotic group (P = 0.1).

CONCLUSION

SF-NGAL level can be used as a diagnostic indicator of PJI. The use of antibiotics before sampling does not affect the SF-NGAL level.