Lodestar DX, an evaluation: loop-mediated isothermal amplification (LAMP) for the diagnosis of urinary tract infection in symptomatic adult females

Abstract

Background

Over 404.6 million people are affected worldwide each year by urinary tract infections (UTIs), with ∼237 000 associated deaths globally in 2019. Much more common in women than men, acute UTI occurs in up to 50% of the female population. Despite this, there is a lack of good diagnostic tools for use at the point-of-care, and over- and under-diagnosis are common, leading to long-term complications and patient suffering, and driving the spread of antimicrobial resistance through insufficient appropriate antibiotic stewardship.

Objectives

To evaluate the performance of a novel point-of-care testing platform, Lodestar DX, in comparison with standard laboratory processing of urine specimens.

Methods

A total of 199 fresh urine samples from symptomatic adult females suspected of having an acute UTI were tested using Lodestar DX and the results compared with standard laboratory methods performed at a local microbiology laboratory.

Results

Using standard laboratory methods, 129/199 samples produced a result and could be compared. Overall sensitivity and specificity of Lodestar DX were 88.1% (95% CI: 77.8%–94.7%) and 83.9% (95% CI: 72.3%–92.0%), respectively (n = 129), with a positive predictive value of 85.5% (95% CI: 76.9%–91.3%), a negative predictive value of 86.7% (95% CI: 77.1%–92.6%) and an overall accuracy of 86.1% (95% CI: 78.9%–91.5%).

Conclusions

The results show good correlation between Lodestar DX results and those of the standard laboratory method for this patient group. However, the platform would benefit from further testing to establish its true point-of-care compatibility and a direct comparison between this and other testing methods, such as urine dipstick testing.