When we measure body temperature we are taking an indirect measurement of the body's blood supply.
The accuracy of such measurements are very much dependent on the tools that we use to measure the temperature and the placement of the thermometer on the subject's body.
Before using any sort of thermometer always read the manufacturer's operating guide first.
You may need to recalibrate the thermometer before you use it the first time and in some cases every time you use it.
Of course you should always follow the operating instructions that are provided with such a tool.
A lot of today's thermometers will make a sound to let you know they have taken a final reading and you can record a number of readings on some so that you have a history of temperatures to refer to.
Other units make sure you clear the last temperature taken before they will make another measurement of temperature.
Many units require special care or cleaning and the instructions will make note of this.
There are a number of helpful note in the instruction guides for these tools, such as suggestions about when not to take someone's temperature.
Times when a temperature can be most misleading are right after strenuous exercise, after a bath or after eating or drinking.
When you take an oral temperature reading you are taking the temperature of the blood as it flows through the veins on the underside of the patient's tongue.
You will place the tip of your thermometer under the patient's tongue and request that he hold it still with his lips and tongue but be careful not to bite the thermometer.
You have to wait at least fifteen minutes after your patient has had a drink or has eaten in order to get an accurate temperature measurement.
After three or four minutes have passed you should have a reliable temperature measurement.
Now if you want to take an axillary reading you will be measuring the temperature of the blood flowing through the axillary artery.
You can easily feel where the axillary artery is if you feel the inside of your subject's arm.
In genral, you should take off the patient's shirt before you begin.
You will them place the end of your thermometer over the axillary artery.
You should then cross your patient's arm over her chest to keep the thermometer in place.
Once again if you have the sort of thermometer that gives you notice when it had taken it's reading you'll wait for the tone before checking the thermometer.
If you are not using a thermometer with a notification tone wait three to four minutes and you should have a good reading.
If you need to do a temperature reading rectally you should first coat the end of the thermometer with an appropriate lubricant.
If your thermometer instructions don't suggest a lubricant to use you can ask you pharmacist or doctor for advice.
You will need to have your patient lying face down on a stable surface such as a bed, or a changing table or your lap for a baby.
Use you r hand at the bottom of her spine to help keep the patient from moving and carefully insert the tip of the thermometer roughly and inch into the anus.
If there is any resistance you have to stop, you should never force the thermometer if it does not go in easily.
Hold the thermometer between your fingers while you cup your hand over the child's buttocks, this should keep the thermometer safely in place until it has taken an accurate reading.