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Pulse oximeter types fall into six main form factors (fingertip, handheld, benchtop, phone-based, wearable and multimodal), and they use one of two sensing methods, transmittance or reflectance. Which regulatory category a given unit sits in depends on its intended use, not its shape. This page puts the three views side by side so a clinic worker, buyer or student can place any device quickly.
This page describes products and general use; it is not medical advice.
Who uses them: clinicians in hospitals and doctors’ offices use medical-purpose oximeters; consumers, athletes and pilots may use general wellness, sporting or aviation units (FDA).
What is a pulse oximeter?
A pulse oximeter is a device that is usually clipped on a fingertip. It uses light to estimate the oxygen saturation of the blood (SpO2) and the pulse rate (FDA, “Pulse Oximeter Basics”). Under 21 CFR 870.2700 an oximeter is a device used to transmit radiation at a known wavelength or wavelengths through blood and to measure blood oxygen saturation from the amount of reflected or scattered radiation. For the full definition and background, see our guide what is a pulse oximeter.
Pulse oximeter types by form
Open Critical Care, which cites the Lifebox Pulse Oximetry Learning Module, lists six main types of pulse oximeter. The table gives what the sources say about each type.
| Type | What the sources say |
|---|---|
| Fingertip | The usual form: a device clipped on a fingertip (FDA). Listed as a main type by Open Critical Care. |
| Handheld | Listed as a main type (Open Critical Care). |
| Benchtop | Listed as a main type (Open Critical Care). |
| Phone-based | Listed as a main type (Open Critical Care). |
| Wearable | Listed as a main type, for example watches (Open Critical Care). |
| Multimodal | Listed as a main type, for example integrated into other types of monitors (Open Critical Care). |
Transmittance vs reflectance oximeters
Separately from shape, oximeters differ in how the light reaches the detector (Open Critical Care).
| Sensing method | How it works | Key difference |
|---|---|---|
| Transmittance | Light is shone through tissue and the detector sits on the far side; typical sites are the fingertip or ear. | The most common type. |
| Reflectance | The sensor sits on the skin and measures light that bounces back. | Inherently more difficult to design to perform well. |
Medical-purpose vs wellness oximeters
The FDA draws its line by intended use, which applies whatever the form factor.
| Category | Where it is used | FDA review |
|---|---|---|
| Medical-purpose oximeter | Mainly hospitals or doctors’ offices; a small number are sold over the counter. | Sold over the counter only after FDA clearance. Oximeters are Class II devices under 21 CFR 870.2700. |
| General wellness, sporting or aviation oximeter | Many are sold directly to consumers. | Not reviewed or evaluated by the agency before being available to the public. |
To check whether a specific model is cleared, see FDA-approved pulse oximeters. In January 2025 the FDA issued a draft guidance, “Pulse Oximeters for Medical Purposes: Non-Clinical and Clinical Performance Testing, Labeling, and Premarket Submission Recommendations” (docket FDA-2023-N-4976). It is a draft, marked not for implementation, and contains non-binding recommendations. It was prompted partly by concern that accuracy can be affected by, among other factors, a person’s skin pigmentation.
How to read a pulse oximeter
Most devices show two or three numbers: SpO2, pulse rate and, on some, a signal-strength value (FDA). Wait a few seconds until the reading stops changing and displays one steady number, then record the value with the date and time. Interpreting a particular person’s reading is a question for their clinician.
How to use a pulse oximeter
The FDA’s reading tips apply to any type:
- Keep the hand warm and relaxed, held below heart level.
- Remove nail polish.
- Sit still while the device reads.
The FDA lists these factors as able to affect accuracy: poor circulation, skin pigmentation, skin thickness, skin temperature, current tobacco use and fingernail polish.
How to choose
The only criterion the sources state is intended use. The FDA separates medical-purpose oximeters, which are cleared before sale, from general wellness, sporting and aviation units, which are not reviewed by the agency beforehand. Clearance status can be checked as described above. For where monitoring devices fit in a wider equipment plan, see clinical alarm management, capnography and blood pressure cuffs; for the product range, see diagnostic and monitoring equipment.
Common mistakes
- Treating a wellness, sporting or aviation oximeter as if it had been reviewed by the FDA. It has not.
- Reading the number before it settles. Wait for one steady number.
- Ignoring conditions the FDA lists as affecting accuracy, such as nail polish, a cold hand or poor circulation.
FAQ
What is a pulse oximeter?
A device, usually clipped on a fingertip, that uses light to estimate blood oxygen saturation (SpO2) and pulse rate (FDA).
How do you read a pulse oximeter?
Wait until the display shows one steady number, then note SpO2 and pulse rate, and record them with the date and time (FDA).
How do you use a pulse oximeter?
Per the FDA: warm, relaxed hand below heart level, nail polish removed, sitting still.
What are the types of pulse oximeter?
Fingertip, handheld, benchtop, phone-based, wearable and multimodal (Open Critical Care), using transmittance or reflectance sensing.
Sources
- U.S. Food and Drug Administration, Pulse Oximeter Basics (checked 2026-10-30).
- 21 CFR 870.2700, Oximeter, via Cornell LII (checked 2026-10-30).
- FDA draft guidance, Pulse Oximeters for Medical Purposes, January 2025 (checked 2026-10-30).
- Open Critical Care, What are the different types of pulse oximeter? and transmittance vs reflectance (checked 2026-10-30).
