Underarm Temperature Chart

Age guidelines for temperature readings

Different age groups have varying norms and considerations for temperature readings. Here are guidelines tailored for each age category (Geneva, et. al, 2019; Peterson, 2007; Standford Medicine Children's Health, 2024):

Infants aged 0-2 years

normal axillary temperature typically ranges between 94.5°F and 99.1°F (34.7°C - 37.3°C). This age group may exhibit slightly wider fluctuations in body temperature compared to older children. A temperature reading below 94.5°F may suggest hypothermia, while anything above 99.1°F could indicate fever.

Children between 3 and 10 years old

The average axillary temperature falls between 96.6°F and 98.0°F (35.9°C - 36.7°C). Temperatures outside this range could signal an underlying condition. A reading of 100.4°F (38°C) or higher generally indicates a fever that may need medical attention, especially if it is accompanied by other symptoms such as lethargy, irritability, or difficulty breathing.

Adolescents and adults aged 11 to 65 years

The typical axillary temperature is between 95°F and 97°F (35°C - 36.1°C). A temperature lower than 95°F could be a sign of hypothermia, particularly in cold environments or after exposure to cold. On the other hand, a fever is usually defined as a temperature of 100.4°F (38°C) or above, at which point medical evaluation is recommended to determine the cause of the elevated temperature.

Older adults aged 65 and older

The average axillary temperature is slightly lower, ranging from 92°F to 97.6°F (33.3°C - 36.4°C). As older adults tend to have lower baseline body temperatures, readings below 92°F could indicate hypothermia, especially in those who are frail or have been exposed to cold conditions. Temperatures above 99°F (37.2°C) should be monitored closely, as even a mild fever in the elderly can be indicative of infection or other health concerns.

Temperature-taking tips

Accurate temperature measurement is crucial for reliable health assessment. Here are some tips to ensure that the child's temperature readings are accurate, particularly when using an underarm (axillary) method:

• Ensure proper placement: For underarm temperature readings, place the thermometer tip in the center of the armpit. Ensure it's in direct contact with the skin, not clothing, to ensure it accurately measures body heat.
• Wait for stabilization: Lower the arm to hold the thermometer snugly against the body after placing it. This helps the thermometer to measure the body's heat accurately.
• Use a reliable thermometer: A digital thermometer is generally more accurate and faster than a glass thermometer with mercury. Ensure the thermometer is in good working condition.
• Avoid recent activity influence: Physical activity, bathing, or hot drinks can affect temperature readings. Wait 15-30 minutes after such activities for a more accurate measurement.
• Record regularly: Consistency is key. Take temperature readings at similar times daily, especially if monitoring fever or illness progression.
• Clean the thermometer: Before and after each use, clean the thermometer with cool, soapy water and rinse thoroughly to ensure hygiene and prevent cross-contamination. Follow the manufacturer's instructions carefully.

Other temperature measurement methods

It's important to note that other methods, such as oral temperature, ear temperature, and rectal temperature, may provide more accurate results than the underarm method, depending on the situation and the patient’s age.

For instance, the rectal thermometer is often considered the most reliable method to measure body temperature, especially in infants and young children, as it gives a closer approximation of the body’s core temperature. Healthcare providers frequently recommend using a rectal thermometer to measure temperature in babies under three months old because it's more precise than the underarm method. Rectal temperatures are typically 0.5°F to 1°F higher than oral readings and provide important diagnostic information when a child has a fever.

The oral method, another common way to check body temperature, is generally suitable for older children and adults. With this method, the thermometer is placed under the tongue, and after waiting for the specified time (usually a minute or two), you can remove the thermometer and read the temperature. It's important that the person being monitored avoids eating or drinking for 15 minutes before taking the reading, as hot or cold substances can alter the result.

The ear temperature (tympanic) method is another reliable option, especially for children over six months old. This method uses an infrared thermometer that measures the heat emitted by the eardrum. It’s quick, easy, and generally well-tolerated by kids, although it's important to use the device correctly for accurate readings. The ear canal must be clear of any obstruction such as earwax, and the thermometer should be properly positioned to get an accurate reading.

References

Geneva, I. I., Cuzzo, B., Fazili, T., & Javaid, W. (2019). Normal body temperature: A systematic review. Open Forum Infectious Diseases, 6(4). https://doi.org/10.1093/ofid/ofz032

Peterson, B. K. (2007, January 1). Chapter 22 - vital signs (M. H. Cameron & L. G. Monroe, Eds.). ScienceDirect; W.B. Saunders. https://www.sciencedirect.com/science/article/abs/pii/B9780721603612500259

Standford Medicine Children's Health. (2024). Taking baby’s temperature. https://www.stanfordchildrens.org/en/topic/default?id=taking-babys-temperature-1-1127