Use of leucocyte esterase reagent strips in the diagnosis or exclusion of prosthetic joint infection.

Abstract

Infection is a leading indication for revision arthroplasty. Established criteria used to diagnose prosthetic joint infection (PJI) include a range of laboratory tests. Leucocyte esterase (LE) is widely used on a colorimetric reagent strip for the diagnosis of urinary tract infections. This inexpensive test may be used for the diagnosis or exclusion of PJI. Aspirates from 30 total hip arthroplasties (THAs) and 79 knee arthroplasties (KA) were analysed for LE activity. Semi-quantitative reagent strip readings of 15, 70, 125 and 500 white blood cells (WBC) were validated against a manual synovial white cell count (WCC). A receiver operating characteristic (ROC) curve was constructed to determine the optimal cut-off point for the semi-quantitative results. Based on established criteria, six THAs and 15 KAs were classified as infected. The optimal cut-off point for the diagnosis of PJI was 97 WBC. The closest semi-quantitative reading for a positive result was 125 WBC, achieving a sensitivity of 81% and a specificity of 93%. The positive and negative predictive values of the LE test strip were 74% and 95% respectively. The LE reagent strip had a high specificity and negative predictive value. A negative result may exclude PJI and negate the need for further diagnostic tests.

• Authors: R Shafafy, W McClatchie, K Chettiar, K Gill, R Hargrove, S Sturridge, A Guyot
• Journal: The bone & joint journal (Bone Joint J) Vol. 97-B Issue 9 Pg. 1232-6 (Sep 2015) ISSN: 2049-4408 [Electronic] England
• PMID: 26330590 (Publication Type: Evaluation Study, Journal Article)
• Copyright: ©2015 The British Editorial Society of Bone & Joint Surgery.

Chemical References

• Biomarkers
• Reagent Strips
• leukocyte esterase
• Carboxylic Ester Hydrolases

Topics

• Arthroplasty, Replacement, Hip
• Arthroplasty, Replacement, Knee
• Biomarkers (blood)
• Carboxylic Ester Hydrolases (blood)
• Colorimetry (methods)
• Female
• Hip Prosthesis (adverse effects)
• Humans
• Knee Prosthesis (adverse effects)
• Leukocyte Count
• Male
• Predictive Value of Tests
• Prosthesis-Related Infections (diagnosis, etiology, microbiology)
• Reagent Strips
• Reproducibility of Results
• Sensitivity and Specificity
• Synovial Fluid (microbiology)