Axillary Temperature

Axillary temperature is the body temperature measured at the axilla or the armpit. It is usually the lowest recorded body temperature when compared to oral, rectal and ear temperatures. The difference in the temperature reading is because the axillary temperature is taken outside the body and the air outside can affect the reading.

The normal axillary temperature range is between 96.6° F and 98° F or 35.9° C to 36.7° C; and a temperature above 99° F is termed as a fever. This method is mostly used to determine the body temperature in babies, young children and patients who have trouble holding a thermometer in their mouth.

While converting axillary temperature to oral temperature, add 0.6 to 0.9° F (0.3 to 0.5° C) to the axillary temperature reading. An axillary temperature reading may be as much as 0.5 to 1.9° F (0.3 to 1.3° C) lower than the rectal temperature reading.

Experts say that the method of measuring body temperature using the axillary method is the least accurate of all. A study was carried out by the Queen's Hospital Croydon where axillary temperatures were taken in 105 patients. The highest reading obtained was 37·4°C (99·32°F) whereas, the lowest reading obtained was 34·0° C (93·20° F).

Thus, the range was 3·4° C (6·12° F). Moreover, the differences between readings in the right axilla and left axilla were as high as 1·4° C. The mean temperature on the right side was 35·84° C, and on the left side was 35·75° C.

The study thus concluded that the concept of a single 'normal' axillary temperature is unsatisfactory. Another study conducted by the Memorial Hospital of Sandusky County, Fremont, Ohio concluded that axillary temperatures are less accurate as compared to rectal and oral temperatures (when measured using an electronic thermometer).

Taking an axillary temperature is the most convenient method to measure body temperature when it comes to babies. But most doctors advice against using this method until your baby is at least 3 months old, due to the need for high accuracy until then. In that case, taking a rectal temperature would be the best option.

But keep in mind that you do not use a mercury thermometer for your baby since breakage can lead to poisoning. Here's how to measure axillary temperature in a baby.

• Clean the thermometer with soap.
• Make sure the baby's armpit is dry.
• Place the tip of the thermometer in the baby's armpit.
• Hold his/her arm firmly against his/her body.

• Remove the thermometer when it beeps.
• Read the temperature on the display.

Body temperature can be measured with highest accuracy by recording rectal temperature. In cases where this method cannot be used, it is best to measure the ear temperature, which gives a reading that is closest to the rectal temperature.

The next best would be oral temperature, as its readings are about 0.5 to 1° F lower than the rectal temperature.

Avoid measuring body temperature if the patient/individual has just taken a bath or has just exercised. These activities increase body temperature leading to incorrect readings. Improper placement of the thermometer, or removing it too quickly, could also give a faulty thermometer reading.

There are many types of thermometers available nowadays, each with its own specifications. So, make sure you follow the given instructions before using the thermometer. While using electronic thermometers, make sure the battery is not weak or dead. When using a glass or mercury thermometer, be careful that it doesn't accidentally break while handling.