This page explains how every guide on hi.doctor is put together, so you can judge how much weight to give it.
Rule one: independent validation
A device is only recommended if an independent body has checked its accuracy. Ratings, price and popularity come after that, never instead of it. Each section has its own standard:
| Section | A device must be |
|---|---|
| Blood Pressure | Listed as validated on validatebp.org (US) or the BIHS list (UK). |
| Thermometers | FDA cleared, with published clinical accuracy. |
| Pulse Oximeters | FDA cleared as a medical device, not sold "for sport use only". |
| Hearing | FDA cleared or registered as an OTC hearing aid. |
| TENS & Pain Relief | FDA cleared for over-the-counter use. |
| Breathing | FDA cleared, or recommended by a respiratory society. |
| Blood Sugar | Meets the ISO 15197:2013 accuracy standard. |
| Scales & Body | Published accuracy, with claims checked against independent research. |
| Kids' Health | FDA cleared, or recommended by a pediatric society. |
| First Aid | Contents checked against Red Cross guidance. |
Every product card shows which list or clearance it passed, with a link, so you can check it for yourself. We also check that the exact model number on the Amazon listing is the one that was validated. Brands often sell near-identical names, and a validated model's cousin is not validated.
Rule two: then buyers have to rate it well
- We have not tested the products we write about. We do not claim to, and we never describe a product as if we had used it.
- Specifications come from the manufacturer's own published listing, and we present them as the manufacturer's figures.
- A validated device must also be well rated by buyers: at least 4.2 out of 5 on Amazon, from at least 500 ratings in the US or 50 in the UK (or 4.0 from 1,000 or more). We use the rating to decide, but do not show it: Amazon's own page has the current one, and it changes.
- US and UK readers see products listed in their own Amazon store. A product sold in only one country is shown only to readers there.
- When buyers report a recurring problem, we summarize it in our own words and say that buyer feedback is the source.
Where the advice comes from
Anything about using a device well (how to measure, which cuff size, when a reading needs attention) comes from medical and public health organizations: chiefly the American Heart Association, the American Medical Association, the NHS, NICE, the FDA and the British and Irish Hypertension Society. Every guide lists the sources it relies on at the end, with links. Where US and UK guidance differ, we say so rather than picking one.
We are not doctors
hi.doctor is not written or reviewed by doctors, and we will never imply otherwise. We help you choose an accurate device; what your readings mean is a conversation for your own doctor. See our medical disclaimer.
Affiliate links
Links to Amazon are affiliate links. If you buy through one, we may earn a commission at no extra cost to you. Commission rates play no part in which products we include or how we rank them.
How we write
Guides are drafted with the help of AI writing tools and then checked against the sources listed on the page. Every health claim should be traceable to one of those sources. If you find one that is not, or anything that is out of date, please tell us and we will correct it.
Keeping guides current
Validation lists, ratings, prices and availability change. We recheck products periodically and remove any that drop off a validation list, fall below our rating bar or disappear from sale.