The detection and estimation of fetal hemoglobin by means of the alkali denaturation test.

By J. H. P. .Joxxis ANI) 1’. H. .J. HUISMAN T HE 1)II”I”El{ENCE in the resistamice of fetal ausd adult hemnoglobimi to alkali has foumid widespread applicatiomi in estimatimig their presemiee qualitit.atively ill the samne blood samuple. Iii 1866, K#{246}rber’ had already noted this diffememice in resistamice iui the 1)100(1 of the miewbormi as compared with that of the adult. In 1935, Brinkmami and .Jomixi& described a muethod (called method I), 1)ased oms the spectrophotommietri( determinat.iomi of the demiat.uration velocity of fetal hemoglobimi (Hh-F). The hemoglobin iii the blood saniples was demiat.ummated by exposure to 0. 1 N Xa011. The niethod of Singer, (1hermioff amid Singer3 (called method II) is based omi the same principle. In this method, the hemoglobimi that. has beemi demiatured by the alkali duirimig the first minute of the reao-tiomi, colisistimig uiiaimily of adult henioglobimi, is precipitated amid removed by filtm-at.iomi. The remaimmimig fetal hemoglobin is miueastmred spectrophotornetrically. Though both miiethods are based omi tise differemice in resist.amice of adult amid fetal hemiioglobin to alkali, there are important differences iii sonic respects. In method I, the demiat.urat.iomi is miieasured by the difference iii t.he light-absorption of oxyhemoglobimi an(1 the optically different denaturatiomi product. With niethod II, a demiatum-ed proteimi is precipitated. It is therefore uncertaims whether the same material is miieasumed by these two muethods. It is possible t.hat dumrimig demiat.uratiomi with alkali, t.he solubility of the prot.eimi is altered at amiother st.age of the deumatuiration pm-oeess t.hami the speetm-umn does. ’ Method II has foumid extemisive use. With t.his teohhsic, and umiprecipitated, one niinute fractiomi ill the blood of adult individuals, rangimsg froni 0.5-1.7 per cemit of the total amount of hemoglobimi, has frequemitly been foumid. Simiger et al.3 do not suppose that this alkali resistamit. fraction (-omisists mainly of Hh-F. It is miot kmiown if this fractiomi represents Hb-F amid other materials as yet unidemitified.4 An increase of this fractiomi was demonstrated imi the 1)100(1 of patieiits sufferimig Irons various forms of anemias, as for example: sickle cell anemiiia,3’ Mediterramieami anemia,2 etc. An imicrease of the alkali m-esistant fraction above 2 per cent is designated as beimig caused by ami increase of fetal hemoglohimi .