QuickCare: How to fix an ER3 message on your thermometer

An ER3 message can happen to your Kinsa QuickCare thermometer if it is moved around a lot during a temperature reading. Please use the following tips to ensure an accurate reading: 

  • Do not bite down or suck on the thermometer while it is in your mouth. This can cause unnecessary movement during the reading and biting down can cause damage to the thermometer.

    For Oral Readings

    Remember to always put the tip in your mouth’s heat pocket; under the tongue at the back of the mouth. 


    The temperature in one spot of the mouth can be very different from another (often varying by a full degree or more) so always put the tip in the same heat pocket for every reading.

    For Rectal Readings

    This is the most effective and accurate way to take a wee baby's temperatures. If you're a new parent, taking a rectal reading might be intimidating, but don’t fret - our very own Nurse Blake has written this fantastic guide just for you.

    Note: Rectal readings can be ~1°F warmer than oral readings.

    For Underarm Readings

    Sleeves and other clothes need to be pulled up and out of the way or they will interfere with readings - the thermometer needs to have complete skin contact. Again, make sure no bathing has occurred before a reading is taken or the temperature might not be accurate.


    • Underarm readings are considered to be the least accurate way of measuring temperature with a stick thermometer, according to the Mayo Clinic.
    • The Kinsa app automatically takes underarm placement into account when calculating the severity of the fever. But it does not use the well-known rule of thumb of artificially adding that 1°F to that underarm reading. Learn more here.