Radiation of wavelength less than m is invisible and is called ultraviolet radiation. Radiation with wavelength from m to m are called X-rays, and radiation shorter than m all the way to vanishingly small wavelength are called gamma-rays. The electromagnetic spectrum is given in Figure 6.1.
1 So, the earlier after a missed period you take a HPT, the harder it is to spot the hCG. 2  If you wait one week after a missed period to test, you are more apt to have an accurate result. 3  Also, testing your urine first thing in the morning may boost the accuracy. So, home pregnancy tests will be accurate as soon as one day after a missed period for some women but not for others. 2  How you use them â Be sure to follow the directions and check the expiration date. 3  When you use them â The amount of hCG in a pregnant womanâs urine increases with time.
Detecting Pregnancy Before You Miss a Period. Women who take pregnancy tests too early often donât have high enough levels of hCG in their body for accurate detection. The most accurate time at which you could take a pregnancy test is if you take one around the time of your period. Negative results can sometimes occur because you arenât actually pregnant, or because you might be ovulating later than you think.