Does henna impact pulse oximeter accuracy?

There have been a few studies that have evaluated the effects of henna on pulse oximetry results. Most of these studies were conducted on normoxic patients (i.e. healthy patients with normal oxygen levels) and found that the SpO2 values from patient fingers with henna dye were not significantly different from values obtained on non-dyed fingers. One study showed that pulse oximeter saturations from henna dyed fingers were significantly higher in patients who were hypoxemic. This means that in the setting of hypoxemia, pulse oximeters placed on body parts with henna dye may show falsely high SpO2 readings. Another study looked at red and black henna in healthy adults and found that red henna had no effect on pulse oximeter reading, but the black henna caused difficulty in obtaining a SpO2 reading. Given these findings, it may be best to choose a finger that does not have henna dye for placement of the pulse oximeter.

References: Çiçek et al, Emerg Med J 2011; Samman et al, Saudi Med J 2006; al-Majed et al, Trop Geogr Med 1994

Keywords: henna, henna dye, henna paste