The DEXA (dual energy X-ray absorptiometry) test is a very accurate way of measurig body fat (a 2-3% margin of error). The DEXA test is used to measure bone density, but thos also measures body fat and where body fat is located.
The DEXA test takes between 10-20 minutes and is a full-body scan using two different low-dose x-rays. This reads both bone mass and soft tissue mass. The test does not cause any discomfort and is very straight forward.
Owing to the precision it is an excellent method of measuring body fat.