transfusion reaction - rachel-la-count

8/6/2019 Transfusion Reaction - Rachel-La-Count

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LabLabinvestigations of investigations of

TransfusionTransfusionReactionsReactions



Types of reactionsTypes of reactions

• Acute (<24 hours)

• Delayed (> 24 hours)



DDx: Acute ReactionsDDx: Acute Reactions

• Immunologic

– Hemolytic

– Fever/chill nonhemolytic

– Urticarial

– Anaphylactic

– TRALI

• Non immunologic

– Transfusion-associated

sepsis– Hypotension due to

ACE-I

– Circulatory overload

– Nonimmune hemolysis– Air embolus

– Hypocalcemia



Sx ImmunologicSx ImmunologicAcute ReactionsAcute Reactions

*Hemolytic Fever, chills, hypotension,oliguria, DIC, back pain,hemoglobinuria

*Fever,nonhemolytic

Fever, chills, vomit, HA

Urticarial Urticaria, pruritus, flushing

Anaphylactic Hypotension, bronchospasm,

urticaria

*TRALI Hypoxia, respiratory failure, fever,hypotension, pulmonary edema



Sx NonimmunologicSx Nonimmunologic

Acute ReactionsAcute Reactions*Sepsis Fever, chills, hypotension

Air embolus Acute SOB, pain, cough, hypotension, cardiac

arrhythmia

Hypothermia Cardiac arrhythmia

Nonimmune

hemolysis

Hemoglobinuria, hemoglobinemia

Circulatory overload Dyspnea, orthopnea, cough, headache,

hypertension

ACEIs Flush, hypotension

Hypocalcemia Tetany, arrhythmia, paresthesia



Acute reactions:Acute reactions:

The role of the clinical teamThe role of the clinical teamIn all non-allergic reactions

• STOP the transfusion

• Keep IV line open with NS (0.9% NaCl)

• RNs: check all labels, armband, forms (did the rightpatient get the right blood?)

• Send a post transfusion blood sample (drawn carefullyso as not to hemolyze the sample)

• Send the rest of the blood bag and tubing to the lab

•Clinical Dr. to evaluate patient:– Signs consistent with anaphylaxis? (bronchospasm)

– TRALI? (hypoxia/respiratory failure/pulmonary edema) – Hemolysis? (brown urine)



ATRs: The labATRs: The lab

• Do 3 steps ASAP:

–Check for clerical errors

–Check for visual hemolysis

–Posttransfusion sample: Reconfirm ABO,do a DAT (is there antibody on thecells?)



The Visual CheckThe Visual Check• What’s checked:

– Plasma or serum postreaction & compare withpretransfusion

– As little as 2.5 mL of hemolysis can be visible

– 0.2 g/L Hb = pink

– 1 g/L Hb or greater = red

– Old sample = may be bilirubin

– Crush injuries = may be myoglobin

• Other causes of hemolysis

– Open heart bypass machines

– Infusion under pressure, small needles

– Drugs added to lines

– Heating or freezing improperly

– Bacterial contamination



The serologic checkThe serologic check

Positive (usually mixed field)

DAT on pretransfusionsample

Negative

Cells rapidly

destroyed

(hemolysis)

Non hemolytic

transfusion reaction

Positive Negative

Missed on initial

testing?

AHTRs, others MORE TESTS

NEEDED!!!



More testsMore tests

• When to do more testing?– If any of the 3 tests (clerical check, hemolysis, repeat

ABO, and DAT) has positive or suspicious results– Or may be policy of BB to do all or some of the

following in all cases:1. ABO: returned bag or segment, pre and post2. Ab screen: pre and post3. Repeat x-match: pre and post samples

• Note: It may be the policy of the BB to call thePathologist after the first 3 tests to ask what todo next. Some BB policies are to do 1-3 in allcases.



Antibody screenAntibody screen

• What if there is now an antibody inthe postreaction sample that wasn’tthere before?

–Clerical or technical error–Pretransfusion: screening cells

represented a single dose (FNs)

–Passive transfer of antibody from arecently transfused component

–Amnestic response: Appearance of alloantibodies can occur within hours of exposure (see DHTR later)



Repeat x-matchRepeat x-match

• Pre and post

–Positive x-match but negative ab screen= may be antibody against low

incidence ag not in screening cells



ID antibodyID antibody

• DAT positive cells: perform elution– Get ab off of cells, run against a panel to

determine specificity

• DAT negative + hemolysis = rapiddestruction– Perform elution, but there may not be ab left

on cells

– Do ab screen on serum, but all ab may have

attached to the RBCs– May have to perform serial DATs and ab

screens: the screen may become positive onceall the ag positive cells are destroyed



When might you getWhen might you get

additional testing?additional testing?• Febrile reactions, >1oC: Just fever = some stop here

– If > 20, other signs of shock: Gram stain/culture of blood bag;suggest patient BCs

• Drop in Hct, visual hemolysis, other testing suspicious or

positive:– LDH– Haptoglobin– Bilirubin (unconjugated)– Urine for free Hb

• Anaphylactic (nonhemolytic):

– Anti-IgA Ab & quantitative IgA• Concern about TRALI

– WBC antibody screen in donor and recipient– CXR for infiltrates



• 1:38,000-70,000(mortality 1: 1,000,000 transfusions)

• Usually due to pre-formed antibody in serum:– ABO incompatibility = #1

– 4 most common abs = anti-A, anti-Kell, anti-Jka, anti-Fya– These bind complement = usually intravascular

• C3a, C5a = anaphylatoxins

• C3b = phagocytes remove

• Membrane attack complex

– Can rarely be due to a very fast amnestic response (hrs)• Extravascular hemolysis = Think Rh

– For complement fixation, need 2 IgGs in close proximity

– Rh ags aren’t close enough on the RBC

Causes of AHTRCauses of AHTR



ABO incompatible plateletsABO incompatible platelets• 5 fatalities from ABO incompatible

platelets over 4 year period• Occurred in cardiac surgery

– A, B, or AB patients receiving multiple non-

group specific platelets over a short period of time

– Anti-A and anti-B in plasma w/platelets

• Solutions for at risk patients:

– Wash platelets– Remove extra plasma by further concentrating– ABO matched platelets



DDx: Delayed ReactionsDDx: Delayed Reactions

• Immunologic:

– Alloimmunization

• RBC antigens

• HLA antigens

– Hemolytic

– GVHD

– Post transfusionpurpura

– Immunomodulation

• Nonimmunologic

– Fe overload



Sx: Delayed ReactionsSx: Delayed Reactions*Alloimmunization:RBC antigens

None, just DAT positive

*Alloimmunization:

HLA antigens

Delayed hemolysis, platelet refractoriness,HDN

*Hemolytic Fever, decreasing Hb, mild jaundice, newpositive DAT or ab screen

GVHD N/V/D, hepatitis, fever, pancytopenia, rash

Posttranfusion

purpura

Thrombocytopenic purpura, bleeding

Immunomodulation Better survival for renal grafts, increasedinfection and tumor recurrence

Fe overload Diabetes, cardiomyopathy, cirrhosis



Delayed Rxns: Lab roleDelayed Rxns: Lab role

• Same work up as acute hemolytic transfusionreaction:

– Immediate procedures:• Clerical check, visual hemolysis, compare positive

posttransfusion DAT to pretransfusion DAT (AABBstandards)

– “As required” procedures (up to discretion of BB ormedical director):• Was there a drop in Hct, clinical signs of hemolysis (fever?)

—can do hapto, bili, LDH

• Post antibody screen to ID ab, elution of DAT (+) cells• Re-do pre antibody screen (tech error?)



Development of anDevelopment of an

AlloantibodyAlloantibody• Usual cause: Secondary, amnestic response– Abs become undetectable, then increase rapidly

after exposure (3-7d)

– Notorious example: anti-Jka and anti-Jkb may

be undetectable in a few weeks to months• In 10 mo: 29% of Kidd abs not detectable• In 5 yrs: 41% not detectable

**Records, patient education important

• Rare causes: Primary allosensitization– New antibody made while sensitizing cells still

circulating

• Time frame: 3d-2wks



Pathophysiology of DHTRPathophysiology of DHTR

• 1:5,000-1:11,000

• Usual abs: Kidd, Rh (E,C,c), Kell (K), andDuffy (Fy)

• Hemolysis typically extravascular

• Delayed serologic transfusion reaction

– Amnestic antibody production does not causedetectable hemolysis

– Just means patient now has new antibody andmust have ag neg cells



Thank you

transfusion reaction - rachel-la-count

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