Impact of Fingernail Polish on Pulse Oximetry Measurements: A Systematic Review

BACKGROUND: The effect of application of fingernail polish on SpO2 measurement remains unclear. We conducted this systematic review to ascertain the impact of fingernail polish on SpO2 measurement. METHODS: We queried PubMed, Embase, and CINAHL databases for publica-tions indexed through December 2022. We included studies providing paired SpO2 data from fin-gertips without and after nail polish application or reporting the number of subjects whose SpO2 could not be measured due to fingernail polish. We used random effects modeling to summarize standardized mean differences (SMDs) and corresponding 95% CI for different nail polish colors from comparative studies. RESULTS: We retrieved 122 studies and included 21 publications, mostly performed on healthy volunteers. Of these, 17 (81.0%) studies had a low risk of bias. We summarized mean SMD for 10 nail polish colors (black, blue, brown, green, orange, pink, purple, red, white, and yellow) from 25 paired data sets on SpO2 across 20 studies. We found small (likely clinically insignificant) but statistically significant differences in mean SpO2 when fingers were coated with black, blue, brown, or purple nail polish (SMD -0.57, -0.47, -0.33, and -0.25, respectively; 95% CI -0.86 to -0.29, -0.84 to -0.10, -0.59 to -0.07, and -0.48 to -0.02, respectively). Only one of 4 studies reported a high proportion of unsuccessful oxim-eter readings from fingers painted with black (88.0%) or brown (36.0%) nail polish. CONCLUSIONS: Although fingernail polish of some colors can marginally reduce SpO2 reading or occasionally impede SpO2 measurement, the variability is clinically insignificant.