3 Ways to Measure a Temperature

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3 Ways to Measure a Temperature
3 Ways to Measure a Temperature

When measuring a person's temperature, the ideal is to use the method that will give the most accurate result possible. In children and infants under the age of five, rectal temperature is more reliable; above this age range, it can be measured orally. In addition, axillary temperature is an alternative for people of any age, but it is not as accurate as others and should not be used in emergency situations.


Method 1 of 3: Measuring Oral Temperature

Take a Temperature Step 2

Step 1. Use a multipurpose or oral digital thermometer

There are digital thermometers that are designed to obtain the temperature through the rectum, mouth or one of the armpits, while others are exclusively oral. Any of them are reliable to take the temperature. Get them at the pharmacy.

It is recommended that you no longer use glass thermometers. Old, they are considered dangerous due to the presence of mercury, a very harmful substance; the thermometer can break and cause a lot of damage

Take a Temperature Step 3

Step 2. After taking a shower, wait at least 20 minutes

A hot bath can affect your body temperature, especially in children, so wait at least 20 minutes for the best possible result.

Take a Temperature Step 4

Step 3. Prepare the thermometer tip

Clean it with alcohol, soap and hot water, then rinse it with cold water and dry it well.

Take a Temperature Step 5

Step 4. Turn on the thermometer and place it under your tongue

The tip needs to be completely in the mouth and under the tongue, covering it completely and away from the lips.

  • When taking a child's temperature, hold the child in her mouth or ask her to do it without moving too much.
  • Try not to move the thermometer too much. The person may be irritable, impatient, or retching; in this case, it is better to get the result through one of the armpits.
Take a Temperature Step 6

Step 5. Remove the thermometer when it starts beeping

Check what is written on the device's digital display to find out if the individual has a fever; values ​​above 38 °C are considered fever. In babies, it is recommended to take them to the doctor even when it is just a fever (37, 3 °C to 37.9 °C). However, children and adults should not need specialized care if the temperature does not exceed 38, 3 °C.

Just in case, go to the doctor so he can prescribe the best way to reduce the fever

Take a Temperature Step 7

Step 6. Before storing the thermometer, wash it in hot, soapy water and dry it

Method 2 of 3: Measuring Axillary Temperature

Take a Temperature Step 9

Step 1. Use a multipurpose digital thermometer, which can take the temperature either in a rectal, oral or axillary way

When you notice that the measurement is high when taken in the armpits, try another way to confirm the presence of fever.

Again, it is recommended to discard glass thermometers. The mercury contained in them is dangerous and will cause damage if the glass breaks

Take a Temperature Step 10

Step 2. Turn on the thermometer and place it in one of your armpits

Raise your arm, position the thermometer and place the tip of it right in the middle of your armpit, covering it completely.

Take a Temperature Step 11

Step 3. When you hear the beep, remove the thermometer

Look at the measured value on the display to find out whether or not there is fever (above 38 °C, which does not require a trip to the hospital, but it is necessary to be attentive to see if the temperature remains, falls or rises):

  • Babies with fever should be treated as soon as possible.
  • Children or adults will need medical treatment if the fever reaches or exceeds 38, 3 °C.
Take a Temperature Step 12

Step 4. Before storing the thermometer, wash it in hot, soapy water and dry it

Method 3 of 3: Measuring Rectal Temperature

Take a Temperature Step 14

Step 1. Use a rectal or multipurpose thermometer

Some of them are intended exclusively to measure temperature through the rectum, while the multipurpose ones can measure it through the mouth, armpits or rectum. Any one of them will give you an accurate result. Buy them at a pharmacy.

  • Look for a model that has a very wide handle to hold, plus a tip that doesn't need to be inserted too deeply into the rectum. This way, it will be easier to get the temperature and will not cause the person as much discomfort.
  • Again, avoid glass thermometers. There is a risk of them breaking and causing irreversible damage due to mercury.
Take a Temperature Step 15

Step 2. For babies, wait 20 minutes to take temperature after bathing or after being rocked

Both can affect the body temperature of babies, so it's best to wait a while to get a more accurate result.

Take a Temperature Step 16

Step 3. Prepare the thermometer tip

Clean it with alcohol and hot soapy water. Afterwards, rinse it with cold water and dry it well. Coat the tip with Vaseline to ease insertion into the anus.

Take a Temperature Step 17

Step 4. Position the baby correctly

He should lie face down in your lap or face up on a firm surface; choose the position that is most comfortable for her and that facilitates her access to the rectum.

Take a Temperature Step 18

Step 5. Turn on the digital thermometer via a button

After a few seconds it will be ready to measure the temperature.

Take a Temperature Step 19

Step 6. Separate the child's buttocks to expose the anus

Carefully insert the thermometer with one hand (deeping it about 1.3 cm, stopping if there is any resistance) and grasp its buttocks with the other.

Hold the thermometer in place by holding it between your middle finger and index finger. At the same time, with the other hand, firmly grasp the baby's buttocks so that he does not move. If the little one gets agitated, remove the thermometer and calm him down, trying again as soon as the little one is calmer

Take a Temperature Step 20

Step 7. As soon as you hear the audible alarm, carefully remove the device

Read the value on the display to find out if the baby has a fever (38 °C or more).

  • Take him to the hospital if the temperature is 38°C or higher.
  • For children or adults, specialized care is needed if the fever reaches or exceeds 38, 3 °C.
Take a Temperature Step 21

Step 8. Wash the thermometer in hot soapy water, rubbing alcohol on the tip as well, and dry it before putting it away


  • See a doctor if you are concerned about a child's health.
  • Use an appropriate digital thermometer to measure the rectal temperature, avoiding contamination of those who are not intended to measure in this way. Rectal thermometers will likely have a different color tip.
  • Buy caps to cover the tip of the thermometer, especially if it is used by multiple people. It will be cleaner that way.
  • Generally speaking, fever is still low up to 38 °C, while those at 40 °C are very high.


  • Always sanitize thermometers right after using them.
  • Go to the emergency room if a baby has a temperature of 38°C or higher.
  • Dispose of mercury thermometers properly. Even the small amount of mercury present in them can cause great harm to the environment if they leak. Do an internet search to find out how these thermometers are disposed of in your city; it may be possible to take it to a location where it is properly disposed of.

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