title: Jk(a-b-) phenotype screening by the urea lysis test in Thai blood donors.
abstract: BACKGROUND
  The Jk(a-b-) phenotype is rare in most populations and often detected after transfusion or pregnancy. After immunisation, anti-Jk3 forms and it can be difficult to find compatible Jk(a-b-) donors. Using anti-Jk(a) and anti-Jk(b) in a conventional tube method is unsuitable for identifying Jk(a-b-) in mass screening of blood donors. Jk(a-b-) phenotypes are associated with the absence of urea transporters on erythrocytes, making red blood cells (RBC) resistant to lysis by 2M urea, while Jk(a+b-), Jk(a-b+) and Jk(a+b+) phenotypes are susceptible to lysis.
  
  
  METHODS
  We screened for Jk(a-b-) phenotypes in blood donors by the urea lysis test using a 96-well microplate. The Jk(a-b-) phenotypes were confirmed by the indirect antiglobulin test (IAT).
  
  
  RESULTS
  Altogether, 20,163 blood samples from Thai blood donors were tested and only RBC from five samples were resistant to lysis by 2M urea, while 20,158 samples were completely lysed within 5 min. In an IAT, both anti-Jk(a) and anti-Jk(b) failed to agglutinate RBC from all five samples. Using a micro-titre plate, the direct urea lysis test, costs * 0.01, about 480 times less than IAT. Moreover, the test time for each plate (94 samples) is about 18 times less than that for IAT.
  
  
  CONCLUSIONS
  Jk(a-b-) phenotype screening by the direct urea lysis test on samples in a micro-titre plate is simple, cost-effective and practical for mass screening of blood donors.
authors.affiliation: Department of Medical Technology, Faculty of Allied Health Sciences Thammasat University, Pathumtani, Thailand.
authors.forename: Suparat
authors.initials: S
authors.lastname: Deelert
authors.forename: Pattrawan
authors.initials: P
authors.lastname: Thippayaboon
authors.forename: Wimolpak
authors.initials: W
authors.lastname: Sriwai
authors.forename: Pramote
authors.initials: P
authors.lastname: Sriwanitchrak
authors.forename: Jintana
authors.initials: J
authors.lastname: Tubrod
authors.forename: Pawinee
authors.initials: P
authors.lastname: Kupatawintu
authors.forename: Oytip
authors.initials: O
authors.lastname: Nathalang
mesh_terms: D001782:Blood Donors; D001788:Blood Grouping and Crossmatching / Q000379:methods*; D005260:Female; D006801:Humans; D007667:Kidd Blood-Group System; D008297:Male; D008403:Mass Screening; D010641:Phenotype; D011247:Pregnancy; D013785:Thailand; D014508:Urea / Q000737:chemistry*
chemical_list: D007667:Kidd Blood-Group System; D014508:Urea