Thermometer Comparison

Rectal
(digital probe thermometer)

~$6 to $20⁴

Lubricate the thermometer tip with petroleum jelly.¹

Lay child face down across lap or place child face up and bend their legs to their chest. Rest your free hand against the back of the child’s thighs.¹

Insert the thermometer ½ inch to 1 inch into the rectum.¹

Hold the thermometer in place until it signals and temperature is displayed.¹

Disinfect thermometers before and after use with soap or an alcohol swab.⁵

Most accurate; considered the standard to measure temperature.^3,6

Patient has a fever if rectal temperature ≥100.4°F (38°C).¹

Recommended route for:

• young children, especially infants <3 months of age.¹
• for patients with neutropenia or when temperature will impact clinical decisions.¹⁰

Invasive potential risk of rectal injury.³

Do not use the same digital thermometer for oral and rectal use. Patients should purchase two thermometers if they intend to use both routes and label each thermometer.¹

Oral
(digital probe thermometer)

~$6 to $20⁴

Wait 15 to 30 minutes after drinking or eating before use.^1,3,5

Place tip of the thermometer under the tongue.¹

Close mouth/lips and breathe through the nose.¹

Do not use teeth to hold the thermometer in place.⁵

Hold the thermometer in place until it signals and temperature is displayed.¹

Patient has a fever if oral temperature ≥100°F (37.8°C).¹

Some patients (especially children) may find it uncomfortable to keep their mouth closed long enough for a reading (usually about one minute).²

For use in children four years or older.⁵

Underarm/Axillary
(digital probe thermometer)

~$6 to $20⁴

Place thermometer under clean and dry armpit.^1,3

Thermometer must be touching skin, not clothing.¹

Hold the thermometer in place until it signals (usually
30 seconds to one minute) and temperature is displayed.¹

Do not use directly after vigorous activity or bathing.³

Less accurate than rectal or oral routes. May be useful for screening.¹

Patient has a fever if axillary temperature ≥99°F (37.2°C).¹

Can be used in children three months and older.¹

If a fever is detected, or there is doubt to the reading, confirm reading with another method.^1,3

Accuracy can be affected by incorrect placement, movement during measurement, and inadequate duration of placement.³

Ear
(digital tympanic thermometer)

~$30 to $50^a

Wait 15 minutes after coming indoors on a cold day before use.⁵

Gently pull the child’s ear straight back if under one year of age. Pull ear up and back if >1 year of age.⁵

Gently insert thermometer probe tip into the ear.¹ Do not use force or push hard.

Follow thermometer directions to ensure the tip is the right distance into the ear canal.¹

Hold the thermometer in place until it signals and temperature is displayed.¹

Patient has a fever if ear temperature is ≥100.4°F (38°C).¹

Uses infrared scanner to measure temperature.¹ Safe to use.¹¹ Does NOT emit radiation or infrared wavelengths into the body. These are sensors which pick up natural infrared wavelengths that the body emits.¹²

Noninvasive and takes only seconds for a reading.

Not recommended in infants <6 months.^1,5

Excessive earwax, a small and/or curved ear canal, ear infections, or improper placement can affect accuracy.^1,3

Can give a reading that is too low.⁶

If used correctly, may be more accurate than oral and axillary temperatures.³

Forehead
(temporal artery thermometer)

Available as touch and non-touch.

Some devices can be used on alternate sites (e.g., wrist, behind the ear, naval, temple), but these sites may not be as accurate as the forehead.^3,11

~$15 to $40^a

To improve accuracy, if moving the device from a hotter or colder area, allow the thermometer to adjust to room temperature for at least 30 minutes.^3,5

Check instructions to see where and how close the thermometer must be to the skin.⁵

For contact devices, gently place flat on the forehead and lightly slide across (maintaining contact) per device directions.^1,3

Not recommended for outdoor use on hot days, in direct sunlight, and/or if there is sweat on the skin.¹⁴

Temperature should not be measured over scar tissue, open wounds, or abrasions.¹⁴

To avoid inaccurate readings, wipe away sweat or dirt and move aside any hair or clothing (e.g., hat, scarf).^3,15

Patient has a fever if forehead temperature is ≥100.4°F (38°C).¹

Uses infrared scanner to measure temperature.^{1,2 Safe} to use.¹¹ Does NOT emit radiation or infrared wavelengths into the body. These are sensors which pick up natural infrared wavelengths that the body emits.¹²

Noninvasive, fast, for all ages. Can be used when sleeping.^1-3,5,7

If used properly, may be the most accurate alternative to a rectal thermometer.^2,3,8 However, prone to user error.^3,9

Accuracy CAN be affected many factors (e.g., a dirty lens, improper positioning).^3,7

Accuracy MIGHT be affected by sex, skin color, and other patient characteristics.⁹

Readings are NOT recommended to make clinical decisions.^9-11

Oral
(digital pacifier thermometer)

~$4 to $14^a

Wait 20 to 30 minutes after drinking or eating before use.³

Inspect for cracks or tears. Don’t use if there are defects.³

The pacifier should be held in the mouth without moving for the instructed time (two to six minutes), until it signals and the temperature is displayed.^2,3

Not recommended (even in newborns), due to lack of accuracy data.^1,2

Noninvasive.

Option for use in infants three months or older when an exact reading is less crucial.³

Color changing strips
(e.g., NexTemp, Tempa DOT)

~<$1 to $6^a

Press strip against forehead, under the arm, under the tongue, etc; depending on manufacturer’s instructions.

Usually reads within one minute.

Clean reusable strips as directed.

Not recommended, due to lack of accuracy and reliability.^1,3,5

Detects changes in skin temperature, but not reliable to measure core body temperature.³

Available as reusable and single-use (usually more expensive).

May be helpful for a quick temperature screening.⁵

Wearable thermometer
~<$1 to $20^a

Follow instructions provided for placement of the sensor (e.g., patch/sticker, watch, sensor device).

Not recommended, due to lack of data and reliability.⁷

Check device instructions, including age for use.

Some devices connect to smartphone apps to track temperature, provide alerts, etc.

Some are stick-on “fever indicators,” which are placed on the forehead for up to 48 hours.¹³

Use an alternate thermometer to confirm readings.¹³