Thermometer, a device used to measure your body temperature must be present in the first aid kit of every house. But, it is important for you to understand the basics before using a thermometer. Measuring your body temperature could be an easy and quick task if done properly. A normal body temperature is approximately 98.6 degrees Fahrenheit (°F) or 37 degrees Celsius (°C). It may not remain constant throughout the 24-hour period and is likely to be lower in the morning, rises during the day and is highest in the late afternoon or evening. It may vary from 1-2°F (½-1°C) from the normal body temperature in some people.
Do you know that you can record your temperature with various thermometers from different parts of your body? Let’s have a look at them.
Types of thermometers
Digital thermometer
It is a small hand-held device with a window that displays your temperature. It is accurate, quick and easy to use. It can take the temperature by mouth, rectum, and armpit. You should not use the same thermometer for recording both oral and rectal readings.
Now taking the temperature is easier with new digital thermometers. Get your own now!
Infrared/ear/tympanic thermometer
It is quick and easy to use. It has a probe which should be cleaned with a cloth and not with water before using. You can also attach a new disposable cover every time you take the temperature to keep the probe clean.
Mercury-in-glass thermometer
It is a thin glass tube with a silver tip and line inside, which is mercury. It can measure oral, rectal or armpit temperature. The tip of the rectal thermometer is usually blue in color to differentiate it from the silver tip of an oral/axillary thermometer. If the thermometer breaks, there is a high probability of swallowing the mercury or it may get absorbed into your skin. As mercury is a toxic agent, avoid using it.
Alcohol-in-glass thermometer
It is similar to mercury-in-glass thermometer but has a red or blue line inside it, which is alcohol. It can be used to measure temperature from the mouth and is safe to use in individuals above 5 years.
Various places to detect temperature
Oral cavity/mouth
It can be used in individuals who are or above 5 years of age. Always remember that the person whose temperature is to be taken should be able to breathe through the nose and is cooperative, or else, you may end up taking a false reading. For measuring the temperature, place the tip of the thermometer under the tongue for 40 seconds or till it beeps. The reference level for fever is > 99.5°F (37.5°C) if the temperature is taken by this method.
Rectum
It can be used in infants, small children, and individuals who are not able to hold a thermometer safely in their mouths. This method provides the most accurate temperature which is usually 0.5-1°F (0.3-0.6°C) higher than oral temperature. The reference level for fever is 100.4°F (> 38°C) if the temperature is recorded by this method.
For recording the temperature, you must apply a lubricant like a vaseline on the bulb of the thermometer to facilitate its insertion. If you are taking the temperature of a child, make him/her lie prone on a lap or a soft padded surface. Spread the buttocks and insert the bulb end about ½-1 inch into the anal canal. Be careful not to insert it very far. Press the buttocks together so that the thermometer stays in place. Remove it after 3 minutes or when the device beeps.
Ear canal
Ear temperature is 0.5-1°F (0.3-0.6°C) higher than an oral temperature reading. The reference level for fever is > 38°C (100.4°F) if the temperature is measured by this method.
If you use it in infants younger than 12 months, pull the earlobe down and back to place the probe in the ear canal. For those above 12 months of age, you should pull the earlobe up and back. You may get a false reading if the thermometer is not placed correctly.
Armpit
Although commonly used, it is comparatively less accurate than oral or rectal methods. For taking the reading, you need to place the thermometer under the arm with the bulb in the center of the armpit. Press the arm against your body and keep the thermometer in place for around 5 minutes or till it beeps. A temperature taken in the armpit is 0.5-1°F (0.3-0.6°C) lower than an oral temperature reading. The reference level for fever is 99.1°F (> 37.3°C) if the temperature is taken by this method.
Forehead
For recording the temperature from the forehead, strip-type thermometers are available. However, they are not very accurate. You need to press the plastic strip firmly against a dry forehead to take the reading. Hold it till the color gets registered (or as mentioned by the manufacturer). The reference level for fever is > 96.8°F (36°C).
Some important tips
1) While selecting a thermometer and method of recording the temperature, always consider the individual’s age and health condition.
2) Avoid drinking or eating 5-10 minutes before recording the oral temperature to prevent faulty readings.
3) If the temperature needs to be taken daily, record it at the same time of each day with the same method.
Your body temperature is one of the parameters for assessing health, therefore, by having knowledge about these things, you can partly be in charge of your own health as well as capable to help people around you.
Further Reading
Feeling Weak Post Fever? Here Is What You Should Do!
10 Things You Should Follow If Your Child Has Fever