MMSC 409 Exam 2 - Complete Solutions (Answered)

MMSC 409 Exam 2 - Complete Solutions (Answered) What is the frequency of the D antigen in white and black populations? white: 85% black: 92% What is the frequency of the C antigen in white and black populations? white: 68% black: 27% What is the frequency of the c antigen in white and black populations? white: 80% black: 97% What is the frequency of the E antigen in white and black populations? white: 29% black: 22% What is the frequency of the e antigen in white and black populations? white: 98% black: 99% What do each of the two loci of the two loci theory code for? Locus 2: codes for presence of Ce, cE, ce, or CE Locus 1: codes for presence or absence of D What chromosome is the Rh gene located on? chromosome 1 What does an Rhnull phenotype mean? no Rh antigens What does an Rhmod phenotype mean? weakened Rh antigens What Rh nomenclature does this describe? - each person inherits set of Rh genes from each parent - codominant - the genotype dictates a person's phenotype - eight combinations of the antigens are possible - **Ags beyond original five are not represented by this nomenclature Fisher-Race What are the 8 combos of antigens possible in the Fisher-Race nomenclature? Dce, DCE, DcE, DCe, dce, dCE, dcE, dCe What Rh nomenclature does this describe? - Based on production of "agglutinogen" by Rh genes. - Up to three antigenic determinants are coded by the gene. Wiener (Rh-Hr) nomenclature In wiener nomenclature, what is Ro? Dce In wiener nomenclature, what is R1? DCe In wiener nomenclature, what is R2? DcE In wiener nomenclature, what is Rz? DCE In wiener nomenclature, what is r? dce In wiener nomenclature, what is r'? dCe In wiener nomenclature, what is r"? dcE In wiener nomenclature, what is r^y? dCE What Rh nomenclature does this describe? - Attempted to organize nomenclatures - D=RH1, C=RH2, E=RH3 c=RH4, e=RH5 - System indicates the presence or absence of antigen on the cell; provides a straightforward description of cell phenotype Rosenfeld What does DCe/dCe look like using Wiener and Rosenfeld nomenclature? R1r' Rh: 1, 2, -3, -4, 5 What Rh nomenclature does this describe? - 6 digit number - First 3 numbers = Blood Group System (e.g., Rh = 004) - Last 3 numbers = Antigen specificity (e.g., 001 = D, 002 = C, 003 = E, 004 = c, 005 =e) International Society of Blood Transfusion (ISBT) What would ISBT 004001 indicate? D antigen What would ISBT 004004 indicate? c antigen Antigens to both alleles present shows what? Heterozygosity Only one antigen from an allelic pair present shows what? Homozygosity What is the difference between the cis and trans effects on phenotyping? Cis effect: interaction occurs bw genes on the same chromosome Trans effect: interaction occurs bw genes on different chromosomes How should you label blood if the weak D test comes back negative? positive? negative - Donor R (Rh) NEG positive - Donor D (Rh) POS When is routine D phenotype testing performed? performed on all donated blood products and all pretransfusion samples, as well as babies born to Rh Neg moms When is weak D testing indicated? when initial D phenotype testing is negative AND: 1) It is a sample from a donated blood product OR: 2) It is a sample from a baby born to an Rh Neg mother Explain the procedure for weak D testing - Incubate the negative (anti-D/pt cells) tube and the Rh Control/pt cells tubes 37C for 15 minutes. Then wash three times with saline - Add 2 drops of AHG reagent (anti-IgG, typically) - Centrifuge and look for agglutination - if pos w/ anti-D only, Stop. - If both neg - add 1 drop of Coombs Control Cells (Check Cells), centrifuge, look for agglutination- if both +, Stop. If either -, repeat In anti-D testing, what do you do if you get a positive test with Rh control? invalidated test, must repeat Why do we need an Rh control for Weak D Testing? AHG reagent cannot distinguish between a positive due to Anti-D coating or a positive due to another antibody coating the red cells What are some common weak D causes?