Understanding the Correct Placement of Probes in Pulse Oximetry Testing

Probes are the clip-shape attachments that come with the pulse oximeter device. These probes read inside the tissue and detect the blood oxygen level. Probes are of three types. There are finger probes which are attached to the finger. Then there are ear probes for the ears (and cheek) and then there are pediatric probes for small babies.

Probe placement in infants:
Before we move on to explain the correct placement of probes in infants, make sure that whatever brand of device is being used, it is approved by the FDA for use on newborns.

Here’s how it should be placed:


  • The placement of probes is actually pretty straightforward. For one, the manual guide that comes with the brand has visualizations and explanations to teach the method. So begin by reading the instructions carefully and follow it verbatim. 
  • If, for any reason the above suggestion cannot be followed then make sure that the probe is attached to the ample part of infants’ hand or foot. 
  • It must be the right hand and foot that should be attached with the probe. Also, ensure that the part of the probe that emits light sensors must be on the top of either appendage. 
  • For the probe to stay in place, the practitioner could use an adhesive tape. However not all adhesive tapes are workable or recommended. Make sure to use the ones suggested by the brand and nothing else. An infant’s skin is sensitive and very delicate; use of an ill-advised adhesive could cause infections.
  • Pediatric probes are different in appearance than adults’. They are larger than finger probes. Ear probes can also be used in infants but on the cheeks instead of on the lobes. They are clip-like and can be placed in a way that one side is inside the cheek and the other outside. It is imperative to make sure that they are clean and free of germs. 

Probe placement in Adults:
Compared to newborns and infants, probe placement in adults is relatively easy. In adults, finger probes work just fine. They are easier to attach allow for movement.

Here’s how they should be attached:


  1. Again, the manual should be referred to before conducting the overnight oximetry test.
  • Remember to place the probes on the fleshy part of the finger and not on the nails.
  • The probe should be clipped in a way that it is not so lose that it falls off and neither so tight that it blocks the blood circulation in the fingers. 
  • Make sure the adult is not wearing any nail polish or henna on the hands; these two interfere harshly with the results and messes up the readings.
  • The room should not have bright or blinding light as it affects the sensors on the probes.

The device is pretty much self-sufficient, all we need to do is place the probes properly and take the readings.