Labs

• QC for ABO reagents: red cells not lysed, no contamination, expiry dates
• Anti-D control allows us to be certain that if we see a reaction, it is due to the Anti-D reacting with the D antigen on the red cell surface, and not some other element of the reagent
• Weak D red cells have the D antigen but have fewer D antigens and/or epitopes per cell than normal Rh-positive cells
• Donors are Du types - must be called D positive if Du comes out positive
• Recipients are not Du typed, would rather consider them as D negative and give them Rh negative blood
• Mothers before they give birth are Du tested to see if they are Rh negative or not
• babies born to D negative moms are Du typed
• atypical antibodies may result from previous transfusions or pregnancies
• antibody screening cells cannot have A/B antigens on red cells
• the last major step before issuing a donor unit to a patient is compatibility testing, aka the major crossmatch
• major crossmatch is in vitro testing (in test tube) of patient plasma with donor packed red cells
• if AC has any agglutination, could be from cold agglutinin or an autoantibody
• autocontrol is patient serum and patient cells, important for autoantibodies
• confirming an antibody

  • select 3 panel cells that should test positive and 3 panel cells that should test negative, can also use screening cells
  • use homozygous to confirm - detects the weakest expression of an antibody
• zygosity in blood banking refers to the heterozygous or homozygous presentation of an antigen on a red blood cells

  some antibodies react better with the homozygous presentation of an antigen
• systems that express dosage: (M/N), (S/s), (Jka/Jkb), (Fya/Fyb), (C/c), (E/e)
• systems that exhibit dosage will present stronger reactions with their corresponding antibodies when both are present, or "positive" on a specific cell in a panel
• an antigen that displays zygosity, or dosage, cannot be officially ruled out unless it is presented homozygously in the panel cell, and th corresponding antibody reaction is still negative
• how we know we have multiple antibodies

  1. we are. not able to make out a clear pattern when we are done
  2. we see reactions strengths varying
• the following antigens are destroyed by anezymes like ficin: M, N, S, s, Duffy
• The following antigens are enhanced by ficin: Rh, Kidd, Lewis, I and P
• Reactivity at Immediate Spin (Room Temperature) suggests IgM/IgG:● ABO antibodies● Rh antibodies● Lewis, P, I, M, and N antibodies
• Reactivity at Lo-Ion ( reducing zeta potential- enhancing reactions) and/or 37 C (increasing possibleantigen-antibody complexes) suggests IgG:● Weaker Rh antibodies
• Reactivity at AHG (IAT) suggests IgG:● Kell antibodies● Rh antibodies● Complement antibodies● Duffy antibodies● Kidd antibodies● S/s antibodies
• what do Screening Cells Contain?•3-5% Reagent red cells (Selectogen Cells) are used.•These cells are Group O•Contain a variation of the most common unexpected antigens that can causeharm to a patient.
•  Zygosity in blood banking refers to the heterozygous or homozygous presentation of an antigen on a red blood cell.
• Positive control– should be heterozygous for the ag being tested in red cell phenotyping
• bruh

  A) 67%

  B) 10%

  
• bruh

  A) 9%

  B) rare

  
• bruh

  A) 22%

  B) 23%

  C) 72%

  D) 55%

  
• IAT (Indirect Antiglobulin Test )

  ● Detects antibody and/or complement attachment to red blood cells in vitro (tube).

  ● Ex. Routine pretransfusion tests will detect developed antibodies made by the patient from a previous blood transfusion or pregnancy.

  ● Antibody screen and panel, Crossmatches.
• DAT (Direct Antiglobulin Test )

  ● Detects antibodies and/or complement coating the surface of red blood cells in vivo (in the body)

  . ● Ex. Follow up test if autocontrol is positive on antibody panel

  ● Done to diagnose:

  ○ Maternal-Fetal Hemorrhage

  ○ Donor incompatibility

  ○ Autoimmune hemolytic anemia
• in DAT

  1. pt's RBCs are coated with Ab
  2. anti-human globulin added
  3. agglutination
• In IAT

  1. patient plasma with antibody
  2. test RBCs and anti-human globulin
  3. agglutination
• DAT is performed when autantibody occurs, alloantibody to antigens on donor RBCs, antibody to drugs (penicillin and cephalosporin), antibody to fetal blood cells that cross placenta
• HDFN - Maternal IgG antibodies attach to fetal red blood cells that crossed the placenta

  and entered maternal circulation from a maternal- fetal hemorrhage during

  pregnancy or at time of delivery.
• Direct Antiglobulin Test (DAT)


  Detects antibodies and/or complement coating the surface of red blood cells in vivo (in the body)

  
• When is DAT performed

  • Autoantibody to red blood cells
  • Alloantibody to antigens on donor red blood cells
  • Antibody to drugs: penicillin and cephalosporin
  • Antibody to fetal blood cells that crossed placenta

  
• DAT in cord blood testing

  • Important for diagnosis of HDFN
  • Maternal IgG antibodies attach to fetal red blood cells that crossed the placenta and entered maternal circulation from a maternal- fetal hemorrhage during pregnancy or at time of delivery
  • A positive DAT on fetal cells indicates maternal-fetal incompatibility and may cause lysis of fetal red blood cells in utero
  • Could lead to hyperbilirubinemia, hemolytic anemia, splenomegaly and hepatomegaly
  • Treatments: UV light for bilirubin breakdown, in extreme cases, exchange transfusion

  
• Positive DAT


  • Critical situation
  • Can be indication of hemolysis occurring inside the body
  • Next step: Elution= to separate antibodies coating the rbc's surface