Laboratory validation and field usability assessment of a point-of-care test for serum bilirubin levels in neonates in a tropical setting

Abstract

Background: Screening and monitoring serum bilirubin (SBR) in neonates is crucial to prevent neonatal hyperbilirubinemia (NH)-associated morbidity and mortality worldwide. A lack of resources is often a barrier for measuring SBR in developing countries. Reliable, cost-effective, easy to use point-of-care (POC) SBR tests are needed. This study aimed to evaluate the technical accuracy and usability of the Bilistick System (BS), a new bilirubin POC test, in a tropical setting. Methods: This was a mixed-methods study, including laboratory validation of the BS, direct observation of technical procedures as performed by the midwives and midwives’ assessment of the device’s easiness of use through focus group discussions (FGD) and a self-administered questionnaire. The study was conducted in a field clinic of the Shoklo Malaria Research Unit along the Thailand-Myanmar border between January and December 2017. Results: A total of 173 samples were tested at a median age of 4 days. BS generated an error message—providing no SBR readout—in 48.6% of the tests performed. For the tests that yielded a result, the correlation coefficient (95% CI) between BS and routine laboratory bilirubinometer SBR was 0.87 (0.77-0.93). The accuracy decreased with increasing haematocrit and at higher humidity (≥75%). Direct observation of the operators using the device and analysis of the focus group discussions and questionnaires indicated that the BS was considered easy to use and required limited training. Conclusions: This evaluation showed that the BS, in its current formulation, does not provide reliable results for measuring SBR in a tropical, low-resource setting but has acceptable usability features.

Diagnostic Properties of a Portable Point-of-Care Method to Measure Bilirubin and a Transcutaneous Bilirubinometer

“…The Bilistick ® underestimated TSB with an MD (±SD) of −22 (±39) µmol/L, with corresponding LoA from −100 to 56 µmol/L. Falsely low Bilistick ® values have been documented in a large study in 4 different countries that its performance [22]. This study confirmed that Bilistick ® values slightly underestimate TSB (−17 µmol/L over a TSB range from 17 to 684 µmol/L).…”

The point-of-care Bilistick method has very short turn-around-time and high accuracy at lower cutoff levels to predict laboratory-measured TSB

“…8 Furthermore, we found that the mean difference in TSB between the two methods was much larger in our study (26.5 µmol/L) than those reported by Coda Zabetta (10 µmol/L) 8 and Thielemans (20 µmol/L). 13 One possible explanation could be the difference in sample sizes, as both of them had much smaller sample sizes than ours. We also did not measure the hematocrit nor the humidity in this study which Thielemans et al 13 showed that these could affect the accuracy of Bilistick readings.…”

“…13 One possible explanation could be the difference in sample sizes, as both of them had much smaller sample sizes than ours. We also did not measure the hematocrit nor the humidity in this study which Thielemans et al 13 showed that these could affect the accuracy of Bilistick readings.…”

“…Although similar, our failure rate was less than were reported by Theilemans et al where 48.6% of their 173 patients tested produced no TSB readings by the Bilistick system. 13 One possible explanation could be due to the level of skills of the testers: the testers in our study were doctors, whereas in the study of Theilemans, their testers were non-medical health workers.…”

“…At the time of preparation of this manuscript, two additional Bilistick studies were reported in the literature. 13,14 None of them had compared the TAT of Bilistick TSB with laboratory TSB. Similar to their findings, we found the combined coefficient of correlation of TSB between the Bilistick and laboratory methods of our two hospitals (r = 0.901) was lower than that reported by Coda Zabetta et al where r = 0.963.…”