QuickCare: How to take a rectal reading on your baby

Ah, rectal readings. We love to hate ‘em. For little ones, under 4 years old they are the gold standard in temp-taking accuracy.

Pro-tip, if taking rectal readings every time you suspect a fever is daunting, try screening with an underarm temp first. If your kiddo's underarm temp is higher than 99°F (37.8°C), then double-check that reading rectally.

Here's how to take a rectal temp like a NICU nurse:

Step 1:   Label the thermometer for ‘Rectal Use Only’ with a permanent marker.

Step 2:   Clean the end of the thermometer using soap and water or rubbing alcohol. Rinse the tip with cool water. Wait a minute for it to reach room temperature again before using it on your babe.

Step 3 Position your little one so they’re comfortable, secure, and still throughout the reading.

  • For little babes, diaper changing position is the easiest - place them on their back and lift their legs up to their chest.
  • For toddlers, try laying them on their stomach, across your lap.

Step 4   Apply a lubricant (like petroleum jelly) to the end of the thermometer.

Step 5   Insert the thermometer into the rectum about ½ to 1 inch. Once you can no longer see the silver tip, that’s ½ inch. Don’t ever try to push past any resistance. Keep your baby’s legs and tushy secure, and wait for the beep. It should take less than 8 seconds!

Step 6   Remove the thermometer and clean it thoroughly, the same way you started. 


* Please note: algorithmic thermometers like the Kinsa QuickCare may produce a slightly higher reading when used rectally.