Editing Triple test (section)

==Variations==

If only two of the hormones above are tested for, then the test is called a double test. A quad test tests an additional hormone, [[inhibin]]. Furthermore, the triple test may be combined with an [[ultrasound]] measurement of [[nuchal translucency]]. {{Citation needed|date=December 2007}}

===Double test===
Free beta hCG and [[Pregnancy-associated plasma protein A|PAPP-A]] are measured. However, the maternal age, weight, ethnicity etc. are still included. In the UK the double test is part of the combined test for prenatal diagnostics.<ref>{{Cite web|url=https://www.nice.org.uk/guidance/cg62/chapter/Key-priorities-for-implementation|title=Antenatal care for uncomplicated pregnancies|date=26 March 2008 |publisher=National Institute for Health and Care Excellende|access-date=10 October 2016}}</ref>

===Quadruple test===
A test of levels of dimeric [[inhibin]] A (DIA) is sometimes added to the other three tests, under the name "quadruple test."<ref name="pmid16700087">{{cite journal |vauthors=Wald NJ, Morris JK, Ibison J, Wu T, George LM |title=Screening in early pregnancy for pre-eclampsia using Down syndrome quadruple test markers |journal=Prenat. Diagn. |volume=26 |issue=6 |pages=559–64 |year=2006 |pmid=16700087 |doi=10.1002/pd.1459|s2cid=1751873 }}</ref> Other names used include "quad test", "quad screen", or "tetra screen."  Inhibin A will be found high in cases of trisomy 21 and unchanged in cases of trisomy 18.<ref name="pmid11494294">{{cite journal |vauthors=Spencer K, Liao AW, Ong CY, Flack NJ, Nicolaides KH |title=Maternal serum activin A and inhibin A in trisomy 18 pregnancies at 10-14 weeks |journal=Prenat Diagn. |volume=21 |issue=7 |pages=571–574 |year=2001 |pmid=11494294 |doi=10.1002/pd.125|s2cid=32154357 }}</ref>

{| class="wikitable"
| '''[[Inhibin]] A''' || '''Associated conditions''' 
 |- 
 | High || [[Trisomy 21]] (Down syndrome)
 |- 
 | Unchanged || [[Trisomy 18]] (Edwards syndrome)
 |-
 | Variable || [[Trisomy 13]] (Patau syndrome)
|}