Buyer's Handbook

Home Health Monitors

Thermometers, blood pressure monitors, pulse oximeters, and glucose meters. What FDA and CDC say about choosing one, how to take a reading you can trust, and the one thing no monitor can do for you.

Reviewed October 2026. We re-check this guide quarterly.

Planning guidance, not medical advice. A home monitor gives you a number. Your health care team tells you what your numbers should be, how often to check, and what to do about them. Nothing here replaces that conversation, and nothing here replaces calling 911 when someone is in trouble.

Start here

A child feels warm at two in the morning, and the thermometer in the drawer is the one you trust

Most of the time, a home monitor earns its place on an ordinary night. A warm forehead, a dizzy spell, a cough that is lingering, a grandparent whose doctor asked for morning readings. The question is never whether to own one. It is whether the one you own gives you a number you can act on, and whether you know how to take that number so the device is not the weak link.

That matters more during a disruption. When the clinic is closed, the roads are bad, or the pharmacy has a line out the door, the household's thermometer and blood pressure cuff become the first instruments anyone reaches for. CDC's advice on home blood pressure is plain: measuring it is the only way to know whether it is high, because high blood pressure usually has no warning signs.[7] The same logic runs through the other three devices.

This handbook covers four monitors. Two of them, the thermometer and the blood pressure monitor, belong in most homes, and we compare them. The other two, the pulse oximeter and the glucose meter, belong in some homes and carry rules that are easy to get wrong. For those we explain what FDA and CDC say so you can have the right conversation with your provider before you buy.

Before you buy

Five questions about who will use it and why

Answer these before any product appears. They decide which of the four devices you need, and which features matter.

1

Who in the house will be measured?

An infant, a child, an adult, an older adult, or all of them. Each thermometer method and each cuff size has an intended range, and a device that fits one person in the house may not fit another.

2

Has a provider asked anyone to track a number at home?

Blood pressure, blood sugar, and oxygen are usually tracked because a clinician asked. If so, ask that clinician what to buy. CDC's blood pressure guidance starts with talking to your health care team about regular home measurement.[7]

3

What is the upper arm circumference of each adult who will use a blood pressure cuff?

Measure it with a tape before you shop. CDC's clinician guide calls an improperly sized cuff the most common error in blood pressure measurement.[8]

4

Who else needs to be able to use it?

CDC suggests that someone else in the house learn to use a glucose meter in case the person who needs it is too sick to check.[12] The same is true of every device here. A large display, a backlight, or spoken results can be the difference.

5

How will you keep the record?

On paper, in the device's memory, or in an app. FDA says changes or trends in oximeter readings may be more meaningful than a single measurement, and CDC says to keep a blood pressure log.[2][7] A device with memory helps only if someone reads it.

How they work

Four devices, four different kinds of number

Each monitor here measures something different in a different way, and each has a failure mode that follows from how it works. Knowing the method is most of knowing what the number is worth.

Thermometers

A digital contact thermometer reads body temperature where it touches: under the tongue, under the arm, in the ear, or rectally, depending on the model and the instructions. A non-contact infrared thermometer reads the surface temperature of the forehead from a short distance. FDA's page on non-contact models is clear that the two are not the same measurement, and that how and where a non-contact thermometer is used affects the reading.[4] FDA also notes that while 98.6°F is usually called normal, studies put normal within a range from 97°F to 99°F.[4] CDC defines a fever as a measured temperature of 100.4°F (38°C) or greater.[6]

Blood pressure monitors

A cuff inflates around the arm, then slowly releases while the device senses the pulse through the cuff. The result is two numbers in millimeters of mercury, the unit CDC describes for the gauge.[7] Home units are automatic and need no stethoscope. CDC says these monitors are easy and safe to use, that evidence shows people with high blood pressure are more likely to lower it when they measure at home with support from their care team, and that the reading depends on things you control: what you ate or drank, how you sit, where your arm rests.[7]

Pulse oximeters

A pulse oximeter clips onto a fingertip and shines light through it to estimate how much of the blood's hemoglobin is carrying oxygen, shown as a percentage, along with the pulse rate. It is an estimate made through skin, which is why FDA lists poor circulation, skin pigmentation, skin thickness, skin temperature, current tobacco use, and fingernail polish as factors that can affect the reading.[1] FDA has been working since 2021 on how well these devices perform across skin tones, including a January 2025 draft guidance on testing and labeling.[3]

Glucose meters

A lancet draws a drop of blood, the drop goes on a disposable test strip, and the strip goes in the meter. In FDA's description, the strip contains chemicals that react with glucose, and the meter measures that reaction with electricity or light, reporting milligrams per deciliter.[9] The strip is the sensor, which is why so much of the guidance about accuracy is about the strips: where they came from, how they were stored, and whether the vial was kept closed.[9] CDC calls monitoring the most important thing a person with diabetes can do to manage it, and says the doctor sets when and how often to check.[12]

Whatever you choose

Take a few readings on ordinary days, when nobody is sick and nothing is wrong. That is how you learn what normal looks like for each person in the house, and it is how you find out that the batteries are weak or the cuff is the wrong size before the night you need the number.

The distinction that matters most

Made for a medical purpose, or sold as wellness

The same shelf holds devices FDA has reviewed for a medical purpose and gadgets it has not. They can look alike. The box, and sometimes the fine print, tells you which is which, and in two of these four categories the difference has a safety warning attached.

Pulse oximeters

Prescription, OTC medical, or wellness

FDA reviews prescription oximeters and requires clinical testing of their accuracy. Over-the-counter oximeters sold for general wellness or for sports and aviation are not intended for medical use and are not reviewed by FDA; over-the-counter devices sold for a medical purpose are reviewed.[2] Read the intended use on the box before the price.

Glucose

No watch measures it

FDA says it has not authorized, cleared, or approved any smartwatch or smart ring that claims to measure or estimate blood glucose on its own, and tells consumers not to buy or use one. The risk it names is a wrong insulin dose from a wrong number.[11] A watch that displays data from an authorized continuous glucose monitor is a different product.

Blood pressure

Upper arm, validated

CDC's clinician guide says the first step in choosing an accurate monitor is one that has passed a formal validation protocol, that upper arm monitors are recommended for accuracy, that wrist cuffs may be used as an alternative for patients who are obese, and that finger cuffs are not accurate and should not be used.[8]

Thermometers are the quiet exception. In June 2025 FDA exempted certain clinical electronic thermometers, those without continuous or thermal-imaging functions, from premarket notification requirements.[4] What still separates a good one from a poor one is the maker's instructions, the stated accuracy, and whether the device is built for the method you will use. For a non-contact model, FDA's own page is a list of the conditions under which it reads wrong.[4]

None of this means the wellness gadget is useless for the purpose on its box. It means it was never tested for the purpose you may have in mind. If a reading will change what someone does about their health, the device producing it should have been reviewed for that job.

Safety: what no home monitor can do

  • It cannot diagnose. FDA says a pulse oximeter is not a substitute for a medical diagnosis, and tells people not to rely only on the reading to assess their condition.[1] That sentence applies to all four devices.
  • It cannot replace symptoms. FDA lists bluish color in the face, lips, or nails, shortness of breath, worsening cough, restlessness, chest pain or tightness, and a fast or racing pulse as signs of low oxygen, and notes some people have none of them. Contact a provider if symptoms are serious or get worse, whatever the number says.[2]
  • It cannot be shared, if it draws blood. FDA says an over-the-counter glucose monitoring system is for single patient use and should not be shared, to reduce the risk of bloodborne pathogen transmission. CDC says the same, especially of lancets, even among family.[9][12]
  • It cannot set your targets. CDC publishes general blood sugar ranges and says in the same breath that your target may differ and to follow your doctor's recommendations.[12] The number you act on is the one your care team gave you.
  • It cannot replace the call. FDA's glucose guidance ends with the plain instruction that for an urgent problem you contact your provider or dial 911.[9] Our guide to care levels and when to call 911 covers the decision.

Reading the box

What to look for, device by device

The features that matter are not the ones in the largest type. For each device, here is what the primary sources say to check, and what the box will not tell you.

Thermometer: method and environment

Decide the method first: a contact thermometer for the mouth, armpit, ear, or rectum, a non-contact model for the forehead, or one of each. The thermometer's instructions and your pediatrician set which method suits which age; follow them. For a non-contact model, FDA says the typical working range is 60.8 to 104°F with humidity below 85 percent, that it should sit in the room 10 to 30 minutes before use, and that the distance from the forehead is specific to each model.[4] If the household still has a glass mercury thermometer, EPA says oral and rectal models hold about 0.61 grams of mercury, that a broken one releases harmful vapor, and that accurate mercury-free digital thermometers are available at any pharmacy.[5]

Blood pressure monitor: cuff, arm, validation

An upper arm cuff, in a size that matches the arm measurement you took, from a model that has passed a formal validation protocol.[8] Makers print the arm circumference range on the box; if two adults in the house fall in different ranges, you may need two cuffs. Memory for at least two users is useful, since CDC asks for at least two readings, 1 or 2 minutes apart, at the same time every day.[7]

Pulse oximeter: intended use and accuracy

The intended use on the box, as above. For a device FDA has cleared, FDA says accuracy is typically within 2 to 3 percent of an arterial blood gas value, so a reading of 90 percent generally means a true value between 86 and 94, and that accuracy is highest between 90 and 100 percent and lowest below 80.[2] A display you can read in a dim room matters more than a Bluetooth logo.

Glucose meter: the strips decide

FDA's list of what to weigh includes accuracy, the blood sample size, ease of use, speed, memory, the medications and supplements that interfere with the test, data transfer, the cost of the meter and the strips, the maker's support line, and features for low vision such as a large display or spoken results, and it says your provider may have a recommendation.[9] The meter is often inexpensive; the strips are the ongoing cost, and FDA says to buy only new, unopened vials authorized for sale in the United States.[10]

Batteries and the drawer

Most of these devices run on button cells or AA and AAA cells, and most spend months in a drawer between uses. EPA notes that the button cell in a digital thermometer may itself contain a small amount of mercury and belongs in a hazardous waste collection, not the trash.[5] Keep a spare of each size with the device. Our disposable batteries handbook covers shelf life and storage.

Checking the device against the clinic

Both CDC and FDA describe the same check. CDC's clinician guide says to bring a home blood pressure monitor to the office, compare it with the office device, and treat a difference of 5 mmHg or less as acceptable and more than 10 as a sign the device may not be accurate, repeating the check annually.[8] FDA says to take a glucose meter to your next appointment, have your provider watch your technique, and compare the meter against a laboratory test.[9]

Technique

The reading is only as good as the two minutes before it

Most wrong numbers at home are not the device's fault. These are the steps FDA and CDC publish, condensed. Keep them with the device.

Blood pressure

  • Nothing to eat or drink for 30 minutes before, and no smoking, alcohol, caffeine, or exercise in that window.
  • Empty your bladder. Sit in a chair with your back supported for at least 5 minutes.
  • Both feet flat, legs uncrossed, arm resting on a table at chest height.
  • Cuff snug but not tight, on bare skin, not over a sleeve.
  • Do not talk. Take at least two readings, 1 or 2 minutes apart, at the same time each day, and write them down.[7]

Pulse oximeter

  • Follow your provider's advice on when and how often, and the maker's instructions.
  • Hand warm, relaxed, and held below the level of the heart. No nail polish on that finger.
  • Sit still and keep the hand still. Wait until the number stops changing.
  • Record the reading with the date and time. Trends mean more than one number.
  • Watch symptoms, not just the display.[2]

Non-contact thermometer

  • A draft-free room, out of direct sun and away from heaters. Let the device sit in the room 10 to 30 minutes first.
  • Forehead clean, dry, and uncovered. No hat, headband, or cosmetic wipe just before.
  • Hold the sensor square to the forehead at the distance the maker specifies, and have the person hold still.
  • Keep the sensor clean and dry; most models must never be immersed.[4]

Glucose meter

  • Wash and dry your hands with soap and warm water. Cold hands restrict blood flow, so warm them first if the drop is slow.
  • Prick the finger, squeeze gently from the base, and place the drop on the strip. Record the result and anything that might have affected it.
  • Dispose of the lancet and strip. Never share lancets, strips, or the meter.[12]
  • Use the fingertip, not a forearm or palm, when you are ill, have just eaten, exercised, or taken insulin, or think your sugar is low.[9]
  • Run a control solution test when you open a new vial of strips, after dropping the meter, and when a result does not match how you feel.[9]

What fails and why

The usual ways a good number goes wrong

The wrong cuff

CDC's clinician guide names an improperly sized cuff as the most common error in blood pressure measurement.[8] A cuff bought for one adult and used on another, or a standard cuff on a large arm, reads wrong every time, and nothing on the display says so.

Strips from the wrong place

FDA warns that pre-owned test strips may have been stored badly, may be expired, may be tampered with, may carry traces of blood, and may not be cleared for sale in the U.S. Instructions not in English, or strips that look different from the brand's others, are its named warning signs.[10]

A forehead in the sun

FDA's page on non-contact thermometers shows the three ways to get it wrong: not square to the forehead, a forehead in direct sunlight, and a device used at the wrong distance.[4] Take the reading indoors, after the device and the person have both been there a while.

Cold hands and painted nails

Two of FDA's listed accuracy factors for an oximeter are skin temperature and fingernail polish; its technique advice is a warm hand and a bare nail.[2] CDC gives the same warning about cold hands for a glucose test.[12]

Strips left in a hot car

CDC says test strips can be damaged by moisture, humidity, or extreme temperatures, and FDA says high altitude and extreme temperature or humidity can have unpredictable effects on results.[12][9] Keep the vial closed and the kit out of the glove box. Our medication storage handbook covers keeping supplies in range during an outage.

One number, read alone

A single high or low reading taken after coffee, an argument, or a flight of stairs is an event, not a trend. CDC asks for two readings a few minutes apart at the same time each day, and FDA says trends in oximeter readings may mean more than one measurement.[7][2] Write it down, repeat it, and call if it holds.

What to buy

Now that you know what to look for

Below is the shortlist of requirements for each device, the same checks we use when we compare them. Our thermometer and blood pressure monitor comparisons are in progress and will appear here when they are finished. We do not publish comparisons of pulse oximeters or glucose meters; for those, the right next step is the conversation with your provider described above.

Affiliate disclosure: New World Survival earns a small commission on qualifying Amazon purchases at no cost to you. This helps us cover operating costs and keep building new content. We only recommend gear we would put in our own kit. Commission never decides a recommendation.

Thermometer

  • Built for the method you will use, with instructions that say so
  • A stated accuracy and working range on the box
  • A display readable at night
  • A battery you can buy anywhere, and a spare
  • For non-contact, a stated measuring distance

Blood pressure monitor

  • Upper arm cuff
  • Passed a formal validation protocol
  • Cuff range that covers each adult's measured arm
  • Memory for two users, or a paper log you will keep
  • Checked against the office device, then yearly

Pulse oximeter

  • Intended for a medical purpose, stated on the box
  • Bought because a provider suggested it
  • A bright display and a steady-reading indicator
  • A plan for what reading means a call

Glucose meter

  • The meter your provider or insurer recommends
  • New strips authorized for U.S. sale, from a pharmacy
  • Control solution on hand
  • One meter per person, never shared
  • Large display or spoken results if eyesight is a concern

Related handbook

Medication Storage and Cooling

Keeping insulin, test strips, and other temperature-sensitive supplies in range when the power is out.

Related handbook

Backup Power for Medical Devices

For the devices in the house that need a plug rather than a button cell.

Comparison

Best Medication Cooler

Coolers and cases for keeping insulin safe through an outage or a trip.

Related handbook

First Aid Kits

The kit these monitors usually live next to.

After you buy

The plan around the number

A monitor is one piece of looking after a household's health. These guides cover the rest: the records, the conditions, and the decision about when a number becomes a call.

Personal Health Records

Where the readings go so a provider can use them.

Heart Conditions and Blood Pressure

Planning for a household that tracks blood pressure through a disruption.

Diabetes

Insulin, strips, and the meter when the pharmacy and the power are both uncertain.

Children's Medical Preparedness

The thermometer, the fever plan, and the pediatrician's number in one place.

Care Levels and When to Call 911

Deciding between watching, calling the nurse line, urgent care, and an ambulance.

Printable Household Medical Profile

One page per person for conditions, medications, and the numbers a provider asked you to track.

All comparisons

Every comparison, in one place

Each comparison we publish for home health monitors is listed here as it is finished. Thermometers and blood pressure monitors come first.

Sources

  1. U.S. Food and Drug Administration. "Pulse Oximeters." Content current as of January 6, 2025. Accessed October 8, 2026. fda.gov
  2. U.S. Food and Drug Administration. "Pulse Oximeter Accuracy and Limitations: FDA Safety Communication." Issued February 19, 2021, updated November 16, 2023. Archived copy linked from FDA's Pulse Oximeters page. Accessed October 8, 2026. fda.gov archive
  3. U.S. Food and Drug Administration. "Pulse Oximeters for Medical Purposes: Non-Clinical and Clinical Performance Testing, Labeling, and Premarket Submission Recommendations." Draft guidance, January 2025, docket FDA-2023-N-4976. Accessed October 8, 2026. fda.gov
  4. U.S. Food and Drug Administration. "Non-contact Infrared Thermometers." Content current as of March 6, 2026. Accessed October 8, 2026. fda.gov
  5. U.S. Environmental Protection Agency. "Mercury Thermometers." Last updated April 8, 2026. Accessed October 8, 2026. epa.gov
  6. Centers for Disease Control and Prevention. "Definitions of Signs, Symptoms, and Conditions of Ill Travelers." Last reviewed May 15, 2024. Accessed October 8, 2026. cdc.gov
  7. Centers for Disease Control and Prevention. "Measuring Your Blood Pressure." September 4, 2026. Accessed October 8, 2026. cdc.gov
  8. Centers for Disease Control and Prevention, Million Hearts. "Self-Measured Blood Pressure Monitoring: Action Steps for Clinicians." December 2014. Accessed October 8, 2026. millionhearts.hhs.gov
  9. U.S. Food and Drug Administration. "Blood Glucose Monitoring Devices." Content current as of November 14, 2024. Accessed October 8, 2026. fda.gov
  10. U.S. Food and Drug Administration. "How to Safely Use Glucose Meters and Test Strips for Diabetes." Consumer update, content current as of November 1, 2021. Accessed October 8, 2026. fda.gov
  11. U.S. Food and Drug Administration. "Do Not Use Smartwatches or Smart Rings to Measure Blood Glucose Levels: FDA Safety Communication." Issued February 21, 2024. Accessed October 8, 2026. fda.gov
  12. Centers for Disease Control and Prevention. "Monitoring Your Blood Sugar." May 15, 2024. Accessed October 8, 2026. cdc.gov

We re-check this guide every quarter as guidance and products change. The Weekly Readiness Brief is a quiet way to hear when it updates.