Rapid and quantitative detection of neutrophil gelatinase-associated lipocalin in synovial fluid using fluorescence immunochromatographic test strips for diagnosing prosthetic joint infections

We developed a rapid and highly sensitive method for quantitatively analyzing neutrophil gelatinase-associated lipocalin (NGAL) levels in synovial fluid and assessed its diagnostic performance for prosthetic joint infection (PJI).We conducted a preliminary analysis of the performance of the developed test strips utilizing clinical specimens to verify their sensitivity, precision, specificity and accuracy.The standard curve of the test strip NGAL values was linear. The detection limit and the limit of quantification (LOQ) were 12.37 and 29.49 ng/mL, respectively, and the approximate detection range was 12.37 to 1250 ng/mL. The interbatch and intrabatch precision of the test strips were each less than 10%, and the cross-reaction rate with competitors' systems was less than 1%.The test strips can be used for the determination of synovial fluid NGAL levels; the test strips are highly sensitive, precise, specific, and stable. Furthermore, they demonstrated good performance in clinical verification.