CHANDIGARH, May 5: Wearing dark-colored nail polish may lead to inaccurate blood oxygen readings on pulse oximeters, according to a recent study by the Department of Pulmonary Medicine at the Post Graduate Institute of Medical Education and Research (PGIMER).
The research team, comprising Dr. Ashutosh N. Aggarwal, Dr. Ritesh Aggarwal, Dr. Sahajal Dhooria, Dr. Kuruswamy T. Prasad, Dr. Inderpaul S. Sehgal, and Dr. Vallappan Muthu, conducted a comprehensive review of global studies examining the impact of nail polish on SpO2 measurements. Their findings were presented during PGIMER’s Research Day celebrations in March.
“Dark nail polish, particularly black, was associated with reduced oxygen saturation readings,” said Dr. Ashutosh Aggarwal. “In clinical or emergency settings, this seemingly minor factor can mislead health professionals and impact decisions.”
The team reviewed 117 studies from major medical databases—PubMed, EMBASE, and CINAHL—published through May 2022. After screening, 21 studies were deemed relevant for final analysis. These focused on the effects of various polish colors, including black, red, blue, and yellow, on pulse oximeter accuracy.
A pulse oximeter is a widely used, non-invasive device that estimates oxygen saturation (SpO2) and heart rate, often clipped to a fingertip. It became commonplace in households during the COVID-19 pandemic.
According to the study, black nail polish lowered SpO2 readings by an average of 0.57 percentage points—a statistically significant difference. In contrast, lighter shades such as yellow, green, and brown showed minimal to no measurable effect.
“While the differences may appear small, for critically ill patients or those monitoring at home, even a slight dip in readings can cause unnecessary alarm or misinterpretation,” said Dr. Ritesh Aggarwal.
The researchers recommend removing dark polish or using an unpainted finger when checking SpO2 levels. This precaution, they say, can help avoid diagnostic errors in both clinical and home settings.
“No single reading should be taken at face value if factors like nail polish are present,” said Dr. Sahajal Dhooria. “Awareness among patients and providers is essential.”
The study was conducted independently and did not receive external funding.
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