No special care is required after a urine test for hCG. If blood is drawn, discomfort or bruising may occur at the puncture site or the person may feel dizzy or faint. Pressure to the puncture site until the bleeding stops reduces bruising; warm packs relieve discomfort. Women who feel faint should be observed until the condition goes away.
Tests for hCG levels pose no direct risk to a woman's health. The main risk with a home pregnancy test is a false-negative result, which may be lessened by following the manufacturer's instructions carefully and waiting at least several days after the expected menstrual period before performing the test. A false-negative result can cause a delay in seeking prenatal care, which can pose a risk to both the woman and her fetus.
HCG levels below 25 mIU/mL will give a negative pregnancy test result for all pregnancy test methods. Home test kits use a cutoff of 50 mIU/mL and will be negative below this level. Following miscarriage or abortion, the pregnancy test may remain positive for four weeks or longer. An hCG test performed during this time may be positive in the absence of pregnancy.
The upper limit of normal for a quantative hCG test is approximately 5 mIU/mL. In rare circumstances, such as pelvic inflammatory disease, the hCG level in nonpregnancy may be greater than 5 mIU/mL. Persons with trophoblastic tumors, molar pregnancies, and choriocarcinoma will have greatly elevated levels of hCG. HCG may be found in persons with testicular cancer and other malignancies that secrete hCG or alpha and/or beta subunits. Quantitative hCG measurement is useful in detecting hCG-secreting tumors. Periodic measurements are useful in evaluating treatment and monitoring patients for recurrence. Maternal serum hCG levels are increased by approximately 25% above normal for the gestational age in Down syndrome pregnancies and in some other trisomy syndromes. In ectopic pregnancy, hCG levels are lower than normal, and the hCG doubling time is less than expected. Minimum hCG increases between timed hCG measurements in the first trimester are:
two measurements one day apart: 29% increase
two measurements two days apart: 66% increase
two measurements three days apart: 114% increase
two measurements four days apart: 175% increase
two measurements five days apart: 255% increase
Recovery of a lower than expected increase is evi dence of ectopic pregnancy. Decreases in hCG are seen in spontaneous abortion.
Victoria DeMoranville, The Gale Group Inc., Gale, Detroit,