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

The effect of application of fingernail polish on S_pO2 measurement remains unclear. We conducted this systematic review to ascertain the impact of fingernail polish on S_pO2 measurement.

We queried PubMed, Embase, and CINAHL databases for publications indexed through December 2022. We included studies providing paired S_pO2 data from fingertips without and after nail polish application or reporting the number of subjects whose S_pO2 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.

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 S_pO2 across 20 studies. We found small (likely clinically insignificant) but statistically significant differences in mean S_pO2 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 oximeter readings from fingers painted with black (88.0%) or brown (36.0%) nail polish.

Although fingernail polish of some colors can marginally reduce S_pO2 reading or occasionally impede S_pO2 measurement, the variability is clinically insignificant.