II. Indications
-
Vasa Previa
- Late Pregnancy Bleeding evaluation
- Infant with black stools thought due to swallowed maternal blood
III. Mechanism
- Differentiates Fetal from Maternal Blood
- Fetal Hemoglobin contains 2 alpha subunits and 2 gamma subunits (contrast with beta subunits in adults)
- Fetal blood is resistant to denaturation when alkali is applied (fetal blood remains pink)
- Adult blood denatures in contact with alkali and turns brown
IV. Technique
- Collect bloody fluid
- Add a small amount of tap water (Hemolyzes blood)
- Centrifuge sampleppp
- Add 5 cc pink supernatant to 1 cc Sodium Hydroxide 1%
- Read in 2 minutes (may be difficult)
- Pink sample indicates fetal Hemoglobin
- Yellow-Brown sample indicates adult Hemoglobin
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Concepts | Laboratory Procedure (T059) |
SnomedCT | 389751005, 390741000, 390483009, 104148009 |
English | Apt test (haemoglobin), stool (procedure), Apt test (haemoglobin), stool, Apt test (hemoglobin), stool, Apt test (hemoglobin), stool (procedure) |
Spanish | prueba Apt (hemoglobina), heces, prueba Apt (hemoglobina), materia fecal (procedimiento), prueba Apt (hemoglobina), materia fecal |