Apt-Downey Test


Other Known Aliases – alkali denaturation test

DefinitionLab test where the blood sample is hemolyzed using sterile water and centrifuged to produce a hemoglobin supernatent.  This is then mixed with 1% NaOH.  Fetal hemoglobin will stay pink, while maternal hemoglobin will turn yellow/brown.


Clinical SignificanceHelps differentiate maternal from fetal blood in cases of vaginal bleeding or neonatal hematemesis/hematochezia.

History – Given to Dr. Leonard Apt and Dr. William Downey, Jr., who were physicians at Harvard Medical School and Children’s Medical Center in Boston, MA in the mid-1900’s.


  1. Firkin BG and Whitwirth JA.  Dictionary of Medical Eponyms. 2nd ed.  New York, NY; Parthenon Publishing Group. 1996.
  2. Yee AJ, Pfiffner P. (2012).  Medical Eponyms (Version 1.4.2) [Mobile Application Software].  Retrieved http://itunes.apple.com
  3. Apt L, Downey WS. Melena neonatorum: the swallowed blood syndrome; a simple test for the differentiation of adult and fetal hemoglobin in bloody stools. The Journal of Pediatrics. 47(1):6-12. 1955. [pubmed]

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