Editing Pregnancy test (section)

=== False positive ===
[[Type I and type II errors|False positive]] pregnancy test results are rare and may occur for several reasons, including:

* user error in performing and interpreting the test,
* biochemical pregnancy (loss of pregnancy before signs of pregnancy are apparent on ultrasound, likely very soon after implantation),
* and non-pregnant production of the hCG molecule (i.e. secretion due to a tumor or the pituitary gland, some diseases of the [[liver]], [[cancer]]s, including [[choriocarcinoma]] and other [[germ cell tumor]]s, [[Selective immunoglobulin A deficiency|IgA deficiencies]], [[Heterophile|heterophile antibodies]], enterocystoplasties, [[gestational trophoblastic disease]]s (GTD), and gestational [[trophoblastic neoplasm]]s).<ref name="ReferenceA2">{{cite journal|last1=Stenman|first1=Ulf-Håkan|last2=Alfthan|first2=Henrik|last3=Hotakainen|first3=Kristina|date=July 2004|title=Human chorionic gonadotropin in cancer|journal=Clinical Biochemistry|volume=37|issue=7|pages=549–561|doi=10.1016/j.clinbiochem.2004.05.008|pmid=15234236}}</ref><ref name=":02" />
* bacterial contamination and blood in urine<ref name="Wallach 2007 https://archive.org/details/interpretationof0000wall_t4n7/page/866 866">{{cite book|last=Wallach|first=Jacques|url=https://archive.org/details/interpretationof0000wall_t4n7|title=Interpretation of diagnostic tests|publisher=Wolters Kluwer Health/Lippincott Williams & Wilkins|year=2007|isbn=978-0-7817-3055-6|edition=8th|location=Philadelphia|page=[https://archive.org/details/interpretationof0000wall_t4n7/page/866 866]|url-access=registration}}</ref>

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.<ref>{{Cite web|title=First Response early result pregnancy test|url=https://www.firstresponse.com/en/product-listings/-/media/81865E866A764C1CAB5B7B340B8E7F60.ashx#.pdf|website=FirstResponse.com}}</ref>

====Due to use of medication====
Urine tests can be falsely positive in those that are taking the medications: [[chlorpromazine]], [[promethazine]], [[phenothiazines]], [[methadone]],<ref name="Wallach 2007 https://archive.org/details/interpretationof0000wall_t4n7/page/866 866"/> [[aspirin]], [[carbamazepine]] and drugs that cause high urinary pH.<ref name=statsp>{{cite journal | vauthors = Betz D, Fane K | title = Human Chorionic Gonadotropin | journal = Statpearls| date = 2020 | pmid = 30422545}}[[File:CC-BY icon.svg|50px]] Text was copied from this source, which is available under a [https://creativecommons.org/licenses/by/4.0/ Creative Commons Attribution 4.0 International License].</ref>