Litt interessant om testing (fra en testoman;)

[Andremann snart? 3.pp]

Klippet fra: http://en.wikipedia.org/wiki/Pregnancy_test

 

Timing of test

False negative readings can occur when testing is done too early. Quantitative blood tests and the most sensitive urine tests usually detect hCG shortly after implantation, which can occur anywhere from 6 to 12 days after ovulation.[1] Less sensitive urine tests and qualitative blood tests may not detect pregnancy until three or four days after implantation. Menstruation occurs on average 14 days after ovulation, so the likelihood of a false negative is low once a menstrual period is late.

 

Ovulation may not occur at a predictable time in the menstrual cycle, however. A number of factors may cause an unexpectedly early or late ovulation, even for women with a history of regular menstrual cycles. Using ovulation predictor kits (OPKs), or charting the fertility signs of cervical mucus or basal body temperature give a more accurate idea of when to test than day-counting alone.

 

The accuracy of a pregnancy test is most closely related to the day of ovulation, not of the act of intercourse or insemination that caused the pregnancy. It is normal for sperm to live up to five days[11] in the fallopian tubes, waiting for ovulation to occur.[12] It could take up to twelve further days for implantation to occur, meaning even the most sensitive pregnancy tests may give false negatives up to seventeen days after the act that caused the pregnancy. Because some home pregnancy tests have high hCG detection thresholds (up to 100 mIU/mL), it may take an additional three or four days for hCG to rise to levels detectable by these tests — meaning false negatives may occur up to three weeks after the act of intercourse or insemination that causes pregnancy.

 

 

[edit] False positives

False positive test results may occur for several reasons. These include: errors of test application, use of drugs containing the assay molecule, and non-pregnant production of the assay molecule.

 

Spurious evaporation lines may appear on many home pregnancy tests if read after the suggested 3–5 minute window or reaction time, independent of an actual pregnancy. False positives may also appear on tests used past their expiration date.

 

A woman who has been given an hCG injection as part of infertility treatment will test positive on pregnancy tests that assay hCG, regardless of her actual pregnancy status. However, some infertility drugs (e.g., clomid) do not contain the hCG hormone.[13]

 

Some diseases of the liver, cancers, and other medical conditions may produce elevated hCG and thus cause a false positive pregnancy test. These include choriocarcinoma and other germ cell tumors, IgA deficiencies, heterophile antibodies, enterocystoplasties, gestational trophoblastic diseases (GTD), and gestational trophoblastic neoplasms (GTN).

 

 

[Andremann snart? 3.pp]

Er nok for spesielt interesserte, har også lest meg frem til at man begynner å produsere hcg når spira fester seg i livmorveggen, som skjer ca 6-12 dager etter EL, dvs at noen vil få positiv test dag 6 etter EL, mens andre må vente til dag 12....