Editing Neonatal heel prick (section)

==Timing==
The blood spot sample should be taken between 48 and 72 hours of age for all babies regardless of medical condition, milk feeding and prematurity.  For the purpose of screening, date of birth is day 0 (some IT systems record date of birth as day 1).<ref>{{cite web|url=http://newbornbloodspot.screening.nhs.uk/standards|title=Standards|work=screening.nhs.uk|access-date=2015-02-07|archive-date=2009-05-01|archive-url=https://web.archive.org/web/20090501152642/http://newbornbloodspot.screening.nhs.uk/standards|url-status=live}}</ref> [[False positive]]s and [[false negative]]s can sometimes occur when the screening tests are performed before 48 hours.<ref>{{cite web|url=http://www.health.vic.gov.au/genetics/nbs.htm |title=Newborn screening guidelines |work=health.vic.gov.au (via archive.org) |url-status=bot: unknown |archive-url=https://web.archive.org/web/20060308182225/http://www.health.vic.gov.au/genetics/nbs.htm |archive-date=2006-03-08 }}</ref>

When the [[immunoassay]] method is utilized as a screening method for quantifying [[17α-hydroxyprogesterone]] (17OHP) in dried blood spots, it exhibits a significant rate of false positive results. As per the clinical practice guideline issued by the Endocrine Society in 2018, employing [[LC-MS/MS]] to measure 17OHP and other adrenal steroid hormones (such as [[21-deoxycortisol]] and androstenedione) is recommended as a supplementary screening approach to enhance the accuracy of positive predictions.<ref name="pmid38169194">{{cite journal |vauthors=Mu D, Sun D, Qian X, Ma X, Qiu L, Cheng X, Yu S |title=Steroid profiling in adrenal disease |journal=Clin Chim Acta |volume=553 |issue= |pages=117749 |date=December 2023 |pmid=38169194 |doi=10.1016/j.cca.2023.117749 |url=}}</ref>

With [[genetic tests]] becoming more common, a wide variety of tests may use the blood drawn by this method. Many neonatal units (SCBUs) now use this method to carry out the daily blood tests (blood count, electrolytes) required to check the progress of ill neonates.{{citation needed|date=June 2020}}