There are so many different brands of pregnancy test kits available in stores these days; it is hard to know what is the best pregnancy test.

All home pregnancy tests work on the same principle; they use monoclonal antibodies to detect the pregnancy hormone, human chorionic gonadotropin or hCG. This hormone is produced when the fertilized egg implants into the wall of the uterus.

The amount of hCG present in the body starts out at very low levels, doubling in quantity each day. The actual amount of hCG varies between individual women. Some pregnancy tests are more sensitive than others, and the more sensitive ones may be able to detect low levels of hCG after just a few days from implant.

How do you use a home pregnancy test kit?

Most brands use the same method for testing. It is your urine you will be testing, as the pregnancy hormone can be detected in the blood or the urine. You use a stick that has an absorbent wick, and either hold it under the stream of urine as you urinate, or you urinate into a clean container and dip the stick into that.

The result is the same regardless of which method you use. You wait for the number of minutes specified on the pack, and then if a line appears, the test is positive; if a cross appears, the test is negative. Some brands further differentiate the results by using different colors for the line and the cross.

What studies have been done to find the best pregnancy test kit?

“Consumer Reports” tested 18 pregnancy test kits in a study to find the best pregnancy test. They worked with an independent laboratory specializing in hCG studies, and tested urine samples with varying amounts of hormone added, to mimic what actually happens in the early days of a new pregnancy. The quantity of hCG was gradually increased until a positive result was obtained.

Each product was tested according to the manufacturer’s instructions, and tests were done at both the minimum and the maximum times stated. The test kits were then rated according to ease of use, efficacy and how easy it was to read the results.

After all testing was completed, the ‘First Response Early Result Pregnancy Test was seen to be the most sensitive and dependable, detecting hCG at extremely low levels. Most of the other test kits were much less sensitive when left for the recommended waiting time, although some performed better when left for the maximum waiting times of ten minutes.

All of the kits tested were classified as easy to use, but three pregnancy test kits, the First Response, ClearBlue Easy and Answer Quick and Simple, were easier to read because their results lines were darker, even at the lower concentrations of hormone.

The final results showed First Response to be the best pregnancy test available, with an over-all rating of excellent. The lowest scoring test kit was Confirm’s Pregnancy Test, with an over-all rating of poor.

Consumer Reports warns that women need to be aware of the limitations of home test kits. Testing for hCG is not the same for everyone, due to variations in the time it takes for the egg to implant, the amount of hormone produced initially and the waiting time for the test to produce a result.