Forehead Thermometer Accuracy

Although, fever is a pretty common ailment, it is often a cause of concern for parents of young children. Even in adults, fever can be dangerous if the cause cannot be diagnosed and it goes untreated for long. Since, most of us tend to treat minor fever at home, determining the body temperature becomes a must to decide the course of treatment.

There are several types of thermometers in the market and each of them has its own set of advantages and shortcomings. The latest type of thermometers to enter the market are forehead thermometers or temporal thermometers. Although, pretty convenient to use, their accuracy is highly questionable.

There are basically two types of forehead thermometers, one in the form of forehead strips and the other, a temporal artery thermometer. Forehead thermometers are very fast and easy to use. Needless to say, they have become quite popular.

Thermometer strips are the easiest to use, as you only have to stick the strip to the forehead of the patient for a stipulated time. The strip contains liquid crystals which react with the surface of the skin. As per the temperature of the skin, the crystals change their color.

The thermometer has a numbered scale which shows temperature for the displayed change in color. These thermometers can be used for babies as well as adults. The cost of these thermometers is about USD 9 to USD 600 per box, depending upon the manufacturer and the number of strips.

In spite of all their advantages, they are considered highly inaccurate. Their inaccuracy, which results in misreading of temperature can pose a threat to the health of the individual.

The second form of forehead temperature is temporal artery thermometer, which uses infrared light for measuring temperature of temporal artery. You just have to scan the forehead with the thermometer, when the infrared light interacts with the temperature of skin and displays the reading through an electronic window. These thermometers are very expensive and may cost you somewhere around USD 30 to USD 150.

The accuracy of a forehead thermometer is more in this case but it is highly heat sensitive. As a result, slight temperature variations affect its reading. If the person has just had a workout and/or is hot and sweaty, then the reading will definitely affect. Temporal thermometers often show a reading that is slightly below the core temperature.

Besides, when you bring the thermometer from a cold room to average room temperature, you have to wait for some time before the thermometer comes to 'normal'. Also, the heat emitted by light sources, which are closely located from the patient's body can interfere with the reading of the thermometer.

Thermometers are classified on the basis of part of the body from where temperature is taken. Depending upon this classification the types of thermometers and their corresponding accuracies are as follows.

Rectal thermometers are considered most accurate, however, they are highly uncomfortable. As they are mostly used for taking temperature in babies and infants, it poses a reasonable amount of risk to the baby's delicate bottom, if the thermometer is not used properly. The temperature exhibited on rectal thermometer scale is often 1º C, more than oral temperature and 1.5º C more than axillary temperature. Rectal thermometers are not used for taking temperature in adults.

The mercury temperatures that are available widely are suitable for taking oral as well as axillary temperature. They have a pretty reasonable accuracy and have become an indispensable part of home first aid kits. However, there is always a risk of breaking the mercury glass thermometer. These days, a mercury free version of oral thermometers is also available. It can be used for taking axillary temperature as well.

Ear thermometer is yet another type of thermometer that is known for its accuracy. However, it is inconvenient to use and the build up of earwax can interfere with the actual temperature reading of the body. Besides, taking temperature from the exact point in ear is tedious.

Forehead thermometer accuracy can be an issue of concern if you are relying on home treatment alone. Thus, one cannot solely depend on these thermometers for home treatment and often needs a backup from any of the other thermometers mentioned above. In short, a digital thermometer that reads the oral or axillary temperature is your best bet.