Antibody Identification and Special Techniques

Antibody Detection and Identification in Blood Banking

• In blood banking, unknowns (patient samples) are always tested against knowns (reagent RBCs or antisera).

  • Patient plasma/serum (unknown) is tested with reagent RBCs (known) for antibody detection or identification.

  • Patient RBCs (unknown) are tested with reagent antisera (known) for antigen typing.

Steps for Antibody Identification and Work-Up

• Step 1: Type & Screen and Initial Interpretation

  • Perform a Type and Screen using the appropriate method (gel, solid phase, or tube) according to facility protocols.

  • Interpret the Antibody Screen results:

    • Negative: Sample is complete; no further testing is needed.

    • Positive: Proceed with antibody identification.

  • Use the Antibody Sheet (Antigram) accompanying the 3-cell screen to document results. A presumptive antibody identification may or may not be possible at this stage.

• Step 2: Full Work-Up & Antibody Identification

  • Set up the required tubes for the Antibody Panel and perform the Antibody Identification (ID) procedure.

  • Record all reaction results on the panel antibody sheet, reconcile all antibody sheets used, and rule out clinically significant antibodies to common antigens.

  • Apply the Rule of Three to confirm antibody identification:

    • 3 antigen-positive cells must be reactive.

    • 3 antigen-negative cells must be non-reactive.

• Step 3: Report Results

  • Ensure accurate antibody identification before reporting final results.

  • Some facilities require a second-person review and documentation before finalizing the antibody conclusion.

  • For complex cases, referral to the IRL (Immunohematology Reference Laboratory) may be considered, based on facility policy.

Pretransfusion, Donor, and Prenatal Testing

• Pretransfusion Testing:

  • Required to detect clinically significant antibodies in recipients of RBC products.

  • Must include incubation at $37°C$ before an antiglobulin test with non-pooled reagent red cells (Standard 5.14.3).

• Donor Testing:

  • Required for allogeneic blood, blood products, and stem/progenitor cells.

  • Antibody identification must follow if clinically significant antibodies are detected (Standard 5.14.3.1).

• Prenatal Testing:

  • Included to assess the risk of hemolytic disease of the fetus and newborn (HDFN).

  • Determines candidacy for Rh-immune globulin prophylaxis (RhIG).

Clinically Significant Antibodies

• Key Points:

  • Usually IgG antibodies.

  • React best at $37°C$ and during the AHG phase (IAT).

• Implications:

  • Can cause hemolytic transfusion reactions (HTRs).

  • Can lead to hemolytic disease of the fetus and newborn (HDFN).

Methods for Antibody Screening

• Tube: Traditional method. Uses enhancement media, chemicals, and enzymes.

• Gel Column: LISS-based agglutination testing; gel traps the agglutinates.

• Solid Phase: Based on microtitration strip wells with bound and dried red blood cell membranes.

• Important Considerations:

  • No single method is superior to another.

  • No method can identify all antibodies with 100% accuracy.

Performing an Antibody Screen by Traditional Method (Tube)

• Label Tubes: I, II, III

• Add:

  • Patient’s plasma: 2 drops to each tube

  • Screen Cells: 1 drop to each tube

  • PeG (usual): 2 drops to each tube

• Antibody screening is performed using the Indirect Antiglobulin Test (IAT).

Antigram

• Screening cells come with a sheet called an antigram that lists the antigens present in each vial.

• Can be single-donor (higher sensitivity) or pooled-donor vials.

• Supplied in sets of 2 or 3 vials to improve detection across different antigenic expressions.

• Screening cells are Group O to prevent interference from anti-A and anti-B antibodies.

• Three-Cell Screens:

  • R1R1 (DCe/Dce)

  • R2R2 (DcE/DcE)

  • rr (ce/ce)

• Two-Cell Screens:

  • R1R1 (DCe/Dce)

  • R2R2 (DcE/Dce)

Screening Cells Phenotypes

• Each vial is phenotyped for at least 18 key antigens, including:

  • Rh System: D, C, E, c, e

  • MNS System: M, N, S, s

  • Lewis System: P1, Lea, Leb

  • Kell System: K, k

  • Kidd System: Jka, Jkb

  • Duffy System: Fya, Fyb

Homozygous vs. Heterozygous Expression

• Importance of Homozygous vs. Heterozygous Expression:

  • Some screening cells should include homozygous (double-dose) antigen expression for accurate antibody exclusion.

• Why Double-Dose Cells Are Important for Antibody Exclusion:

  • More antigen = better sensitivity in detecting weak antibodies.

  • If a double-dose cell is non-reactive, we can confidently exclude that antibody.

Homozygous vs Heterozygous Phenotypes in Blood Group Systems

• Homozygous Expression (Double-Dose)

  • Stronger antigen expression.

  • More reliable for ruling out antibodies.

  • Example: Jka Jka (homozygous for Jka).

  • Homozygous for Jka → Double-dose expression.

  • Higher antigen density leads to stronger reactions if the corresponding antibody is present.

• Heterozygous Expression (Single-Dose)

  • Weaker antigen expression (dosage effect).

  • Less reliable for ruling out antibodies.

  • Example: Jka Jkb (heterozygous for Jka and Jkb).

  • Heterozygous for Jka and Jkb → Single-dose expression.

  • Weaker antigen density can result in reduced or undetectable reactivity in some cases.

Dosage Effect in Antibody Testing

• Homozygous (Double Dose) = Stronger reactions

• Heterozygous (Single Dose) = Weaker reactions

• Important for: Rh (except D), Kidd, Duffy, MNS systems

Antithetical Antigens

• Antithetical antigens are paired antigens that arise from allelic genes (inherited variations at the same genetic locus).

• Individuals inherit one antigen from each parent, meaning they will only express one of the two in each pair.

• Examples of Antithetical Antigens:

  • Kell System: K vs. k, Kpa vs. Kpb, Jsa vs. Jsb

  • Kidd System: Jka vs. Jkb

  • Duffy System: Fya vs. Fyb

  • MNS System: M vs. N, S vs. s

Key Challenges in Antibody Detection

• Antibody Titer Below Sensitivity Threshold:

  • Low-concentration antibodies may go undetected.

  • Can lead to false negatives in routine screening.

• Lack of Homozygous Expression on Screening Cells:

  • Many screening cells express antigens heterozygously, leading to weaker reactivity.

  • Reduces sensitivity, making it harder to detect antibodies showing dosage effects.

• Low-Prevalence Antigens and Antibodies:

  • Rare antigens may not be included in standard screening panels.

  • Antibodies against these antigens may be missed unless specifically tested.

  • Exclusion using double-dose cells is difficult since these antigens are often heterozygous or untested.

Antibody Identification

• When antibodies are detected, additional testing shall be performed to identify antibodies of clinical significance.

• In patients with a history of previously identified antibodies, testing shall be capable of detecting and identifying the presence of newly formed clinically significant antibodies.

Following a Positive Antibody Screen

• Antibody Identification

Panel Antigram

• Patient serum reactions with reagent red cells & phases of testing

• An autocontrol should also be run with ALL panels

Panel Cells

• Each of the panel cells has been antigen typed (shown on antigram)

• "+" refers to the presence of the antigen

• "0" refers to the absence of the antigen

• Example: Panel Cell #10 has 9 antigens present: c, e, f, M, s, Leb, k, Fya, and Jka

General Exclusion Rules

• Exclude antibodies that could not be responsible for the reactivity seen

• "Rule-out" technique ‒ Identify all reagent cells that were non-reactive when tested against patient’s serum.

• Example: Cell #8:

  • Evaluate homozygous expression of antigens on non-reactive cells.

  • Rule out antibodies that would have reacted against homozygous antigen if they were truly present in the patient’s serum.

• Among the antibodies to common antigens as prescribed by the FDA that are ruled out include anti-c, -e, - k, -Fyb, -Jka, -Lea, -M, and –S.

Autocontrol

• Patient’s serum with his or her own RBCs

• Autocontrol is incubated with the antibody screen or antibody panel (facility-dependent policy)

• If an autocontrol is positive, run a DAT (patient cells plus AHG) to detect in vivo coating

• The AC and DAT can help in determining if the antibodies are directed against the patient’s cells or transfused cells (allo- or autoantibody)

• Autocontrol & DAT Interpretation:

  1. Positive autocontrol or DAT → Autoantibody or alloantibody is present (consider recent transfusion).

  2. Negative autocontrol → Suggests alloantibody.

  3. Positive autocontrol but negative DAT → Possible false-positive reaction.

Rules for Ruling-In and Ruling-Out Antibodies

• The laboratory shall:

  1. Evaluate available historical patient information and antibody history.

  2. Exclude commonly encountered clinically significant red cell alloantibodies.

  3. Assign new antibody specificity after demonstrating reactivity with at least two antigen-positive red cell samples and nonreactivity with at least two antigen-negative red cell samples.

Facility Policy for Ruling-In and Ruling-Out Antibodies

• Ruling Out Antibodies:

  1. Use one homozygous (double-dose) cell to rule out antibodies.

  2. If a homozygous cell is unavailable, apply exception criteria.

• Ruling In Antibodies – Rule of 3 and 3:

  1. Confirm antibody presence with:

     1. Reactivity with 3 antigen-positive cells.

     2. Non-reactivity with 3 antigen-negative cells.

• Understanding the Rule of Three:

  1. A statistical guideline ensuring confidence in antibody identification.

  2. A p-value ($\leq 0.05$) supports this rule, indicating a 95% confidence interval, meaning there is only a 5% chance of random error.

  3. If the panel doesn’t have enough cells, additional cells from another lot should be used.

• Confirming with Antigen Typing:

  1. Performed only if the patient has not been recently transfused (to avoid donor cell interference).

  2. A negative reaction with reagent antisera confirms the antibody (antigen is absent on the patient’s RBCs).

Key Rule for Ruling Out Antibodies

• If an antigen-positive red cell is non-reactive, the corresponding antibody is not present in the patient’s plasma.

Ruling Out (Usual Facility Policy)

• Key Rule: If an antigen-positive red cell is non-reactive, the corresponding antibody is not present in the patient’s plasma.

• Ruled out: anti- D, -M, -s, -P1, -Leb, -k, and -Fyb

• Rh: Anti-D, -C, -c, -E, -e, -f

• Kell: Anti-K, -k

• Duffy: Anti-Fya, -Fyb

• Kidd: Anti-Jka, -Jkb

• MNS: Anti-M, -N, -S, -s

• Lewis: Anti-Lea, -Leb

• P1 group: Anti-P1

More Examples of Ruling Out Antibodies

• Key Rule: If an antigen-positive red cell is non-reactive, the corresponding antibody is not present in the patient’s plasma.

• anti-f, -Fya, -E, -c, -Jka, -Lea, -Jkb, -C, -e, -N, and anti-S

Antibody Identified: Anti-K

• This fulfills the "Rule of Three:"

  • Panel Cells 2, 4, and 5 (also 6, 8, 9, and 10) are negative for the K antigen and did not give a reaction at AHG phase.

  • Panel Cells 1, 3, and 7 are positive for the K antigen and gave a reaction at AHG phase.

• Ruled out: anti- D, -M, -s, -P1, -Leb, -k, -Fyb, anti-f, -Fya, -E, -c, -Jka, -Lea, -Jkb, -C, -e, -N, and anti-S

• The autocontrol is negative.

• 0

Phenotyping the Patient

• Another way to confirm the presence of antibody is to determine the patient’s phenotype for antigen

• Individuals do not make alloantibodies toward antigens on their own RBCs

• If the patient has recently been transfused, RBC separation techniques should be used before phenotyping is done

• Key Rule: The patient’s cells should type antigen-negative unless the specificity is an autoantibody.

• Remember Landsteiner’s Rule: Individuals do not produce alloantibodies against their own antigens.

Tube Methodology

• No Enhancement: Saline

• Enhancement: Albumin (Bovine Albumin), PEG (Polyethylene Glycol), LISS (Low Ionic Strength Solution)

• Enzymes: Papain or Ficin

• Chemicals: DTT, CDP, EGA

• Gel and solid-phase methods can’t resolve most serological problems.

Saline-IAT

• USE: Antibodies historically reactive at PEG and LISS

• Procedure: 2 drops plasma + 1 drop RBC susp. Mix and incubate for 30 mins – 1 HR. Mix, centrifuge and read @ $37°C$. Wash 3-4x with saline. Completely decant and add 2 drops of anti-IgG. Mix, centrifuge, dislodge gently and read immediately.

• Note: Add one drop of check cells to all negative tubes.

• A saline-IAT – no enhancement media to increase antibody binding at $37°C$ incubation.

• Incubation time = 30-60 minutes (for maximum antibody binding to occur)

• Subject to a direct agglutination reading at immediate spin, room temperature, and $37°C$ incubation.

• Useful when all cells tested are reactive with PEG and LISS enhancement media. Ex. Cold autoantibody

• Appropriate for tests performed at $37°C$ or lower temperatures.

Albumin

• First widely used additive solution.

• Decreases the repulsive forces that keep red blood cells (RBCs) apart (Intercellular distance).

• Enables some RBC antibodies (ex. Rh system) to directly agglutinate antigen-positive RBCs at $37°C$.

• Minimally impacts antibody binding by an indirect antiglobulin test (IAT).

• Helps separation of RBC antibody specificities when one or more antibodies are present at $37°C$ incubation.

• Warm autoantibodies maybe decreased in albumin IATs, allowing identification of underlying alloantibodies.

• 22 or 30%Bovine Serum Albumin (BSA)

PEG (Polyethylene Glycol)

• Most sensitive potentiator used for antibody detection.

• Centrifugation with PEG causes false positive results, so reading at $37°C$ is omitted.

• USE: Antibody screen, ID, crossmatch, Warm autoadsorption, Elution

• NOTE: ADD ONE DROP OF CHECK CELLS TO ALL NEGATIVE TUBES.

• Procedure: 2 drops plasma + 1 drop rbc susp + 2 drops peg. Mix and incubate @ $37°C$ for 15 mins. Mix and wash 3-4x directly with saline. Completely decant and add 2 drops of anti-IgG. Mix, centrifuge, dislodge gently and read immediately.

LISS (Low Ionic Strength Solution)

• Less sensitive than PEG but may detect antigen-antibody reaction at $37°C$ incubation.

• USE: PEG enhanced warm or cold autoantibodies, PEG related antibody.

• Important to keep the ratio of LISS to plasma to cell suspension = 2:2:1.

• Procedure: 2 drops plasma + 2 drops LISS + 1 drop RBC susp. Mix and incubate @ $37°C$, 15 mins. Mix, centrifuge and read at $37°C$ before washing. Wash 3-4x with saline. Completely decant and add 2 drops of anti-IgG. Mix, centrifuge, dislodge gently and read immediately.

• Note: Add one drop of check cells to all negative tubes.

DTT (Dithiothreitol)

• known reducing agent.

• 0.2 M DTT

  • Mitigates serological interference from anti-CD38 drugs (Daratumumab, isatuximab, etc.): To be able to identify underlying alloantibodies to common blood group antigens Or in the presence of an antibody to a high frequency antigen susceptible to DTT treatment.

  • May denature/weaken: Kell group except Kx, Dombrock, Cartwright, Lutheran, JMH, LW, and most Knops blood group antigens.

• 0.01 M DTT

  • Reduces the disulfide bonds of IgM molecules.

  • Used for red cells that spontaneously agglutinate due to heavy coating with IgM autoantibodies.

  • Can also be used to treat serum inorder to distinguish IgM from IgG antibodies.

  • It is expected to decrease complement binding activity of IgM.

  • It cleaves disulfide bonds of IgM molecules and abolishes the agglutinating ability of IgM antibodies while leaving IgG antibodies unaffected.

FICIN

• not to be used as the only method.

• Rationale: When sialic acid is removed by proteolytic enzymes from the RBC surface, the surface charge is altered, denaturing some blood group antigens and leaving others more accessible.

• Enhances: ABO, Rh, Kidd, Lewis, P1, I, Vel, cold and warm autoantibodies

• Destroys: Duffy, MNS (some examples of little s), Xga

Chloroquine Diphosphate (CDP)

• IMPORTANT: Follow the manufacturer's package insert for testing procedures.

• CDP treatment can make red blood cells IgG-negative in patients with a positive direct antiglobulin test (DAT) due to IgG.

• Chloroquine diphosphate (CDP) removes IgG from red blood cells.

• Can potentially remove HLA (Bg) antigens from red blood cells to aid in antibody identification.

• DAT-negative red blood cells after CDP treatment can be used for antigen typing, autocontrol testing, or autoadsorption.

• Saline-reactive and monoclonal blood grouping reagents may not work well with CDP-treated red blood cells.

• Interpret CDP treatment results carefully as it may affect red blood cell surface antigens.

EDTA GLYCINE-ACID (EGA)

• This procedure dissociates IgG from RBCs, preserving common RBC antigens for subsequent testing with the IAT method.

• Procedure:

  • Place 5 drops of packed patient RBCs in a labeled tube.

  • Wash patient RBCs at least three times with 0.9% blood bank buffered saline.

  • Re-suspend patient RBCs in 0.9% blood bank buffered saline to a concentration of 3-5%.

  • Place 7 drops of the washed patient RBCs in a labeled tube.

  • Select a panel or screen cell for positive control, and place 7 drops in a labeled tube.

  • Centrifuge patient and positive control cells for 1 minute at 3400 rpm, and carefully remove supernatant.

  • Prepare EDTA glycine-acid solution by adding 2 drops of EGA Solution #1 to 8 drops of EGA Solution #2 in a separate test tube.

  • Add 5 drops of freshly prepared EDTA glycine-acid solution to patient RBCs and positive control cells.

  • Mix gently and start a timer, allowing the mixture to stand at room temperature for not longer than two minutes.

  • Add 1 drop of EGA Solution #3 to each tube to stop the treatment process.

  • Mix thoroughly and centrifuge for 30 seconds at 3400 rpm.

  • Discard supernatant and re-suspend treated RBCs in saline. If RBCs are not markedly tanned or clumped, wash the cells three times with 0.9% blood bank buffered saline.

  • Re-suspend patient's cells and positive control cells to a concentration of 3-5%.

• EGA treated patient's RBCs negative with 6% albumin in IAT method indicate readiness for testing with IAT method.

• Antigen type EDTA Glycine-acid treated positive control cells in parallel; they should still be positive.

• Use untreated antigen-negative cells as a control for negative antigen typing.

Hypotonic Saline Wash (Osmotic Lysis)

• NOTE: Used if patient has been transfused within the last 3 months.

• Red blood cells (RBCs) from patients with Hemoglobin S (HgbS) or Sickle Cell Disease (SCD) are resistant to lysis by hypotonic saline.

• Procedure:

  • Start with 0.9% NaCl and dilute to 0.3% NaCl.

  • Wash the RBCs until no hemolysis is observed.

Reticulocytes Separation

• NOTE: Do not use this procedure for patients with HgbS. Use hypotonic wash instead.

• Some patients may not produce adequate reticulocytes (i.e., aplastic anemia). If needed, perform red cell molecular genotyping.

• High-speed centrifugation isolates reticulocytes from mature RBCs.

• Mature RBCs are denser and sediment faster than reticulocytes.

• Requires a fresh sample less than 24 hours old.

• Separate the top 3-5 mm of the red cell column.

• Focus on young cells, unaffected by recent transfusions.

PEG Autoadsorption

• 1 mL each: Cells, Plasma, PEG

• Incubation: $37°C$, 15 minutes

• Centrifuge, transfer adsorbed plasma to second tube, if needed.

• Generally, with two adsorptions the warm autoantibody is removed.

• 4 drops adsorbed plasma for testing used.

• Loss or weakening of antibody activity using PEG adsorption reported.

• If DAT strongly positive (e.g. >2+), pre-treat the cells (e.g. ficin)

RESt Adsorption (Rabbit Erythrocyte Stroma)

• Cold antibodies interfere with ABO/Rh testing and compatibility testing (xmatch).

• Known to also adsorb anti-B, anti-Vel and anti-P1.

• Used to adsorb cold auto anti-I or auto anti-IH.

• For potent cold autoantibody showing at $37°C$ and antiglobulin phase of testing.

• These cold autoantibodies: auto anti-I, -H or -IH bind to Rabbit erythrocyte stroma (RESt).

• Results of RESt-adsorbed plasma compared with unadsorbed to confirm the presence of the cold autoagglutinin and detect underlying alloantibodies.

• Cold antibodies are generally not clinically significant.

RESt Adsorption (Rabbit Erythrocyte Stroma) Doesn't Remove

• Not adsorbed/removed: IgG anti-D, -C, -E, -e, -c, -K, -k, -Kpa , -Kpb , -Jsa , -Jsb , -Fya , -Fyb , - Jka , -Jkb , -Lea , -Leb , -Lua , -Lub , -M, -N, -S, -s, -Xga, and –Tja

• Caution: Failure to aspirate the RESt suspending diluent completely will result in dilution of the plasma. Clinically significant weakly reactive antibodies may be missed.

Prewarm Technique

• CAUTION: Use only when all alloantibodies have been ruled out or identified. Do not use just to eliminate unidentified reactivity as some potentially significant weak antibodies could be missed by pre-warm technique.

• Negative – Could be due to IgM cold reacting antibody.

• Positive – Could be due to an IgG clinically significant antibody or cold autoantibodies that persist in warmer temperatures exhibiting a broad thermal amplitude.

• Room Temperature reactive IgM antibodies are generally clinically insignificant.

Applying Special Techniques

• Hospital Blood Bank:

  • Cold Auto Workup: RT/4C incubation, RESt Adsorption, Prewarm Technique, Allos exclusion with LISS

  • Warm Autoantibody Workup: Allos exclusion by LISS and PEG Autoadsorption, if eligible

  • Anti-CD38 Drug: 0.2M DTT treatment of reagent red cells

  • IgM spontaneous agglutination: 0.01M DTT treatment of RBC

  • Sickle patient phenotyping, if transfused within 3 months: Hypotonic Wash/Osmotic Lysis

  • HLA/Bg: CDP (available but rarely used)

  • IgG phenotyping: EGA treatment of DAT-IgG(+) RBC

• Tests Sent to an IRL

  • HTLA

  • High incidence Ab

  • UNRESOLVED Warm/Cold Autoantibodies

  • DAT with positive (saline) control

  • Monocyte Monolayer Assay (MMA)

  • Thermal Amplitude Study

  • Reticulocytes harvest by microhematocrit centrifugation – recently transfused patient

  • Molecular testing/Genotyping

Antibodies Seen in Hospital Blood Bank

• Antibodies causing a few or some reagent red cells reactive:

  • Single Antibodies

  • Antibodies to Low Frequency Antigens

  • Antibody to HLA (Human Leukocytes Antigen)

  • Cold Alloantibody

• Antibodies causing all reagent red cells reactive:

  • Multiple Antibodies

  • Antibodies to High Frequency Antigens

  • HTLA-like

  • Drug Therapy

  • Monoclonal Antibodies: anti-CD38, anti-CD47

  • Reagent-related Antibodies

  • Antibody to Drugs

  • Warm Autoantibody

  • Cold Autoantibody

Antibody Picture

• Single antibody – uniform reactivity

• Multiple antibodies – variable reactivity

• High incidence, HTLA-like, anti-CD38, anti-CD47 – all cells reactive

• HLA/Bg – 1 or few cells reactive

• Low incidence – specifically points to a low incidence antigen positive cell on the antigram/panel.

More Antibody Pictures

• Warm Auto – all cells reactive including the autocontrol, DAT positive, Eluate panagglutinin

• Cold Auto – variable reactivity at all phases including the autocontrol. All (almost all) cells react more strongly at I.S., RT and 4C. In some cases, autocontrol/DAT may not be detectable. Could be of high thermal range and reactive at 37C/AHG; Eluate negative.

• IgM/Cold Alloantibody – stronger in reactivity at I.S./RT or 4C than at AHG (if AHG demonstrable), autocontrol negative.

Still More Antibody Pictures

• Reagent related due to additive/enhancement – all cells reactive including autocontrol, DAT negative.

• Reagent related due to reagent red cells diluent/preservative/antibiotic – all cells positive, except the autocontrol. Washing the reagent red cells should resolve the issue.

• Antibody to Drugs – DAT positive, Eluate negative

• IMPORTANT: Always verify transfusion history and previously identified antibodies.

Case 1

• 51 y.o. male. Hgb was 6.8 on admission, so patient was transfused with 1U PRBC with dialysis. Hgb=8.0 post transfusion. Blood Group: O+

• Unable to perform antigen typing due to recent transfusion.

• Give E and c negative RBCs

Reticulocytes Separation for Transfused Patients

• NOTE: Do not use this procedure for patients with HgbS.

• High speed centrifugation separate reticulocytes from mature RBCs by sedimentation.

• As mature RBCs are denser (heavier) than young reticulocytes, they sediment more rapidly than reticulocytes.

Case 2

• Gel antibody screen POSITIVE.

Case 3

• Female, 65 years. Requires RBC transfusions.

• History of transfusion: 2 units last month.

Rule of Three

• Positive plasma reaction with 3 reagent red cells that carry the corresponding antigen.

• Negative plasma reaction with 3 cells that lack the corresponding antigen.

• 95% confidence interval; p-value $≤ 0.05$

Case 4

• A 66 y.o. male, in follow-up. On Daratumumab (anti-CD38 Monoclonal Antibody Drug). Hematologic History: IgG-Lambda Multiple Myeloma. He has a long medical history list and is taking several medications.

• ABO/Rh Typing

• Antibody Screen (Tube)

What is Anti-CD38 (Daratumumab)?

• Daratumumab (DARA) is a drug approved by the FDA for refractory multiple myeloma treatment.

• An antibody directed against CD38 expressed on multiple myeloma cells.

• Human IgG1K monoclonal antibody that targets the CD38 glycoprotein.

Case 5

• A type and crossmatch was ordered on a 58 y.o. female patient under anti-CD47 monoclonal antibody drug therapy.

• A type and crossmatch was requested for a 58-year-old female patient receiving anti-CD47 monoclonal antibody therapy.

Adsorption

• Transfused within the last 3 months?

  • No

  • Yes

    • Autoadsorption: PEG, ZZAP

• Perform Allogeneic Adsorption: One-cell or Differential

• Warning: Removes antibody to high frequency antigens

• Summarized the essential serological tests for accurate antibody identification.

• Assessed various strategies for detecting and identifying antibodies in different clinical scenarios.

• Applied advanced techniques to resolve complex red cell antibody challenges effectively.