If your child has a rash and the doctor suspects scarlet fever, he or she will usually take a throat culture (a painless swab of throat secretions) to see if the bacteria grow in the laboratory. If a strep infection is confirmed, the doctor will prescribe an antibiotic for your child to be taken for about 10 days.
Pregnancy tests are designed to tell if your urine or blood contains a hormone called human chorionic gonadotropin (hCG). This hormone is produced right after a fertilized egg attaches to the wall of a woman's uterus. This usually happens -- but not always -- about six days after fertilization.
This hormone is released after the fertilized egg attaches itself to the wall of your uterus, while its amounts increase as the pregnancy progresses. How soon a pregnancy test will be able to detect this hormone depends on its sensitivity because some are able to detect HCG only when released in large enough amounts. As a result, a pregnancy test that is not able to detect small amounts of HCG will give you a negative result if you take it too soon.