blood bank lab exam

• saline (low protein)
• high protein  
• low protein 
• monoclonal antibodies

• IgM
• low protein based 
• used to test for cells already coated with IgG antibody
• disadvantage: cost, long incubation time, cannot test for weak D

• faster
• can weak D test
• disadvantages: requires control tube, increased false positives
• if control is positive, test is invalid

• consists of a combination of various monoclonal anti-D reagents from different clones in order to ensure reactivity with a broad spectrum of Rh positive RBCs
• can be used for slide, tube, microwell and automated testing

• pipette tip should not go past the gel
• 0.8% cell suspension for forward typing
• gel particles are composed of beads of dextran acrylamide
• advantage: more sensitive and more standardized than tubing
• disadvantage: cannot test hemolyzed samples. lipemic samples will clog the gel. Rouleux caused by high protein conct in serum with patients with multiple myeloma or waldenstrom's macroglobinemia

• recently transfused
• bone marrow transplant

• monoclonal antibody
• IgM
• blue
• Anti -A1 lectin: dolichos bilforus

• monoclonal antibody
• IgM
• yellow

• group O
• cells are suspended in 2 - 5% diluent

• 22% albumin
• LISS (low ionic strength solution)
• PEG (polyethylene Glycol
• AHG

• reduces zeta potential allowing RBCs to approach each other and increase chances of agglutination.
• zeta potential: difference in electrical potential between RBC surface and outer layer of ionic cloud

lowers zeta potential and increases uptake of antibody onto RBC, thus reducing incubation time

• removes water from the test system, concentrating the antibodies present
• thus increasing the degree of RBC sensitization.
• more sensitive than LISS, albumin, saline.
• do not use PEG with pt specimen with increased protein concentration such as multiple myeloma

• allows for agglutination of incomplete antibodies
• contains antibodies to both IgG and complement

must be controlled by adding Coombs control cells (check cells)

• They are Rh + coated with anti D
• will react with anti IgG in the AHG reagent resulting in visible agglutination.
• Addition of coombs control cells proves that AHG is working properly
• must show a positive result to validate. if negative (no agglutination) the test must be repeated

• cannot detect low titer antibodies
• cannot detect low frequency antigens that are not present on any of the RBCs in the screen cell set
• false negative reactions occur due to postzone when antigen is in excess
• temperature and phase of reactivity
• length of incubation
• pH: antibodies react best at a neutral pH between 6.8 and 7.2

• transfused within past 3 months
• medications
• autoimmune disorders
• infections

• ability to screen for multiple antigens at one time 
• no interference from recent transfusion or positives DAT on RBCs
• not limited due to lack of rare anti sera
• able to screen large numbers of donors in a short time

• selected panel cells
• enzymes
• neutralization
• adsorption

• done after ABID
• testing additional panels with minimal overlap in antigens they possess

• treating panel cells with enzymes destroying certain antigens and enhancing expression of others
• sulfyhydryl - DTT, 2-ME. destroys kell
• ZZAP - denatures kell, MNS, Duffy

• when autoantibodies are suspected, its best to use the patients own RBCs to adsorb the autoantibody.
• autologous cells are first washed to remove unbound antibody
• cells are incubated with patients serum. temperature is dependent on adsorbing either cold or warm antibody.
• sample is inspected for signs of agglutination throughout incubation period. agglutination means that RBC binding sites are saturated with autoantibody.
• serum is then harvested and incubated several times with new aliquots
• if no agglutination is apparent during incubation the harvested serum is tested against patient's own RBCs