Exam II Clin Flashcards
what is a “secretor”
someone who is capable of making ABO antigens in their secretions (like saliva) and plasma
what autoantibodies does an O blood person have
what autoantibodies does an A blood person have
what autoantibodies does an B blood person have
what autoantibodies does an AB blood person have
type O: anti-A, anti-B, anti-A,B
typeA: anti-b
type B: anti-a
type AB: none
how does leukemia affect ABO antigen expression
decreased antigen
describe acquired B phenomenon
pt w/ intestinal obstruction –> increases bowl permeability –> bacterial polysaccharides enter circulation and are absorbed by group A cells –> N-acetylcysteine is converted to a-galactosamine (similar to B antigen) –> positive B antigen test results
how does gastric or pancreatic carcinoma affect expression of ABO antigen
serum contains excessive blood group specific soluble substances (BGSS) which neutralizes the antisera used in forward grouping
describe bombay phenotype of RBCs and what autoantibodies those patients have
what blood can bombay pts receive
absence of H (Oh)
anti-A, anti-B, anti-AB, anti-H
(anti-H IgM binds complement and lyses cells)
pts can only receive bombay blood
in bombay patients, what are the consequences of the anti-H antigen
1) intravascular hemolysis (anti-H can activate complement cascade which lyses RBCs)
2) transfusion reaction (acute hemolytic transfusion reaction)
3) hemolytic disease of the newborn
what is needed to produce Rh antibodies
exposure to the antigen (pregnancy or transfusion)
describe the Kell system antibodies
K = kell k = cellano (most are kk)
IgG antibodies that react at 37 degrees celsius
can cause hemolytic disease of the newborn and a hemolytic transfusion rxn
“kell kills”
the McLeod phenotype of a patient with kell system antibodies is associated with what conditions
1) chronic compensated hemolytic anemia and presence of acanthocytes (spur cells) on peripheral blood smear
2) chronic granulomatous disease (CGD)
- lack of NADH-oxidase
describe the Kidd system antibodies and what they are associated with
anti-Jka (kidd a) and anti-Jkb (kidd b)
associated with delayed hemolytic transfusion reactions (IgG)
the antibodies “disappear” meaning no antibodies are detected during the initial antibody screen and cross match –> antibodies reappear upon transfusion with Kidd + unit
describe the duffy system antibodies
what are they associated with
describe how race affects antibodies
Fya (duffy a) and Fyb (duffy b)
hemolytic disease of the newborn and hemolytic transfusion reactions
caucasians: Fy(a+b+) or Fy(a+b-) or Fy(a-b+)
african americans: Fy(a-b-)
why are the Fy(a-b-) duffy antibodies moer often seen in african americans as compared to caucasians
b/c the Fy(a-b-) phenotype is resistant to Plasmodium vivax infection
describe the MNS system antibodies and what they are associated with
anti-M & anti-N and anti-S & anti-s
usually IgM, non-hemolytic usually
describe Lewis system antibodies and what they are associated with
naturally occurring, usually IgM “warm” anti-Le antibodies found in secretions and plasma
rather mild - “lewis lives”
compare type and screen and crossmatching
type and screen: only ABO, Rh, and Ab screen performed
crossmatch: tests all those things plus actual testing of patient’s serum compatibility w/ donor cells (mixed recipient serum with donor RBCs to detect agglutination)
what is the indirect coombs test (IAT) used for
in what patients is it used
tests pt’s SERUM for developed antibodies against foreign RBCs
uses serum (Ab must NOT be bound to RBC to enable detection)
used prior to blood transfusion and in prenatal testing of pregnant women
describe the direct coombs test (DAT)
when is it used
tests for Ab of complement proteins attached to the RBCs
uses washed red blood cells w/o plasma
used to detect autoimmune hemolytic anemia and in transfusion reaction work ups
describe the phases of the indirect coombs test (IAT)
room temp phase:
- initial combination of patient sera w/ commercial suspension of RBCs
- detection of “cold” IgM Ab
37 degrees C phase:
- detection of “warm” IgM-IgG Ab mixture
- Rh, Kell, Kidd, and Duffy system detections
Anti-Human globulin (AHG) phase:
- detection of “warm” IgG Ab that coat RBC membrane
Check Cell phase:
- verify AHG was added and working
what are the reticulocyte, unconjucated bilirubin, and haptoglobin levels in autoimmune hemolytic anemia
increased reticulocyte
increased unconjugated bilirubin
decreased haptoglobin
what symptoms are characteristic of intravascular hemolysis
hemoglobinemia and hemoglobinuria
how do you confirm autoimmune hemolytic anemia
DAT (direct coombs) and characterization of auto-Ab as cold or warm reactive
what is the most common autoAb
benign cold agglutinin
most commonly auto-anti-I
because cold autoantibodies can obscure alloantibodies, what should you use when doing an alloantibody test
prewarm or autoabsorbed serum
3 causes of warm autoimmune hemolytic anemia
idiopathic, SLE associated, drug-induced
treatment for warm autoantibody positive autoimmune hemolytic anemia
splenectomy and steroids
what infections are associated with cold agglutinin AIHA
mycoplasma pneumoniae or infectious mononucleosis
what can O+ patients receive
what can O+ patients donate
receive: O+ and O-
donate: O+, A+, B+, AB+
what can A+ patients receive
what can A+ patients donate
receive: A+, O+, O-, A-
donate: A+, AB+
what can B+ patient receive
what can B+ patients donate
receive: O+, B+, O-, B-
donate: B+, AB+
what can AB+ patients receive
what can AB+ patients donate
receive: everything
donate: AB+
what can O- patients receive
what can O- patients donate
receive: O-
donate: everything
what can A- patients receive
what can A- patients donate
receive: O-, A-
donate: A+, AB+, A-, AB-
what can B- patients receive
what can B- patients donate
receive: O-, B-
donate: B+, AB+, B-, AB-
what can AB- patients receive
what can AB- patients donate
receive: O-, A-, B-, AB-
donate: AB+, AB-
common viral causes of transfusion reactions
HIV, HTLV-1, Hep B, Hep C
what lab/tests need to be done after a transfusion reaction occurs
- direct coombs
- ABO/Rh on pre and post samples
- IAT
- repeat crossmatch
- send donor unit for gram stain and culture
- follow up with hemoglobin/hematocrit and urine for hemolysis
- rule out TRALI
symptoms of acute hemolytic transfusion reaction
hypOtension, hemoglobinuria, DIC, flank pain, infusion site pain, fever, chills, N/V
symptoms of delayed hemolytic transfusion reaction
unexplained rise in unconjugated hemoglobin, drop in hemoglobin/hematocrit
symptoms of febrile non-hemolytic transfusion reaction
fever, chills, hypERtension
symptoms of allergic transfusion reaction
urticarial rxn, erythema, cutaneous flushing, laryngeal edema, bronchoconstriction, N/V/D
symptoms of TRALI
non-cardiogenic pulmonary edema
lack of abnormal breath sounds, no signs of cardiac failure
pulmonary arterial wedge pressure NOT elevated
resolves 48-96 hours from onset
symptoms of septic transfusion reaction
fever, chills, rigors, shock
common cause of septic transfusion reaction
usually contaminated platelets (since they have to be stored at room temperature)
describe acute hemolytic transfusion reactions
presents within 24 hours
pre-existing natural IgM Abs induce complement-mediated intravascular hemolysis
describe delayed hemolytic transfusion reactions
presents after 24 hours post transfusion
IgG reaction from prior transfusion/exposure causing extravascular hemolysis
what are the levels of LDH, bilirubin, haptoglobin, and leukocytes in delayed hemolytic transfusion reaction
- increased LDH
- increased bilirubin
- decreased haptoglobin
- leukocytosis
treatment for delayed hemolytic transfusion reaction
IVIG
what type of transfusion reaction can cause sickle crisis in sickle patients
delayed hemolytic transfusion reaction
describe febrile non-hemolytic transfusion reaction
what is the treatment
rise in temp of 1C or greater in 30min-1hour after transfusion
caused by acquired Ab to leukocyte Ag in transfused products (attributed to pyrogenic cytokines in units during storage)
tx: anti-pyretic (NO ASA)
prevention and treatment for allergic transfusion rxn
pre-medicate with antihistamine
intubate prn, O2 prn, IV antihistamine
prevention and treatment of severe allergic (anaphylactic) transfusion rxn
give IgA deficient products to prevent anti-IgA antibodies, pre-medicate with antihistamine or steroids
epi, diphenhydramine, aminophylline
describe TRALI
who is it often seen in
Ab bind with MHC class 1 Ag on neutrophils
seen in multiparous women
bacterial contamination of packed cells and platelets often results from what species
packed cells: yersinia enterocolitica and Pseudomonas (due to ability to grow at low temp and high iron environment)
platelets: staph, strep, salmonella, escherichia, serratia
what tests does donated blood undergo
- ABO and Rh groups, unexpected RBC antibodies
- Hep B and C, HIV-1 and 2, HTLV-1 and 2, west nile, syphilis
- trypanosoma cruzi (Chaga’s)
- NAT testing (nucleic amplification testing for RNA of viruses or DNA of HBV)
list the thresholds for RBC transfusions
- increased oxygen carrying capacity (pt is hypoxic)
- Hgb < 7 or Hct < 21% in an otherwise healthy individual w/ acute anemia
- Hgb 7-9 in pt w/ cardiovascular or cerebrovascular risk factors
- HbS 30-50% in sickle cell patients to prevent stroke
indications for transfusing packed red blood cells (PRBCs)
contraindications for transfusing PRBCs
SYMPTOMATIC anemia as a result of increased loss, decreased survival, or decreased production of RBCs
contraindications: volume expansion, coagulation deficiency, drug treatable anemia
indications for transfusing frozen/deglyced RBCs
hypersensitivity to plasma proteins
indications for transfusing washed RBCs
recurrent severe allergic rxn to unwashed RBCs
indications for transfusing irradiated RBCs
risk of GVHD in immunocompromised pt
indications for transfusing leukocyte reduced RBCs
febrile rxns due to leukocyte antibodies
indications for transfusion of platelets
contraindications
what is the threshold
bleeding due to thrombocytopenia
contraindications: plasma coagulation deficit, ITP, TTP
<10,000 platelets in absence of bleeding
<50,000 platelets w/ significant hemorrhage
<100,000 platelets w/ risk of CNS bleed
what are “pooled” platelets
6 single units of platelets from whole blood pooled into a single standard dose (six pack)
5.5 x 10^10 platelets
80 mg fibrinogen
what are pheresis platelets
from a single donor, automated cell separator
decreased exposure to single donors, increased platelet retention
what are irradiated platelets
leuko-reduced platelets to reduced risk of GVHD
what are the contents of fresh frozen plasma
all coagulation factors, 400 mg fibrinogen, very few RBC, WBC, or platelets
indications and contraindications for fresh frozen plasma
indications: deficiency of stable and labile plasma coagulation factors (ex: emergent reversal of warfarin, TTP) with or without bleeding
contraindications: volume expansion
threshold for transfusing fresh frozen plasma
prophylactic: PT or PTT prolonged and active risk of bleeding
documented factor deficiency in bleeding pt
isolated factor deficiency for which factor derivative unavailable
indications cryoprecipitate transfusion
threshold?
Hemophilia A, vWF disease, hypofibrinogenemia DIC, bleeding uremia pt, topical glue
threshold: fibrinogen < 80 with ongoing bleed
contents cryoprecipitate
150-250 mg fibrinogen
80-120 units vWF
40-60 units Factor 8
what is in RhoGAM
when is it used
immunoglobulin made from human plasma with high levels of polyclonal Ab against D antigen
- Rh negative mom with an Rh positive fetus/neonate
- transfusion of Rh positive blood to Rh negative pt
- treatment of ITP
what is the Kleihauer-Betke test
measures fetal Hgb in mother’s circulation
when is RhoGAM given
1 full dose at 26-28 weeks or within 72 hours of Rh+ infant
what is solvent detergent treated plasma (SDP plasma)
pooled plasma from up to 2500 donors
inactivates enveloped viruses (HIV and Hep B)
what is granulocyte pheresis
indications?
hazards?
contains WBC 1 x 10^10, platelets 3x10^11
indications: neutropenia unresponsive to appropriate antibiotics
hazards: allergic and febrile rxns
what is the only substance that can be transfused with blood
normal saline
infusions must be completed in what time
4 hours
what specific sterile technique is used in neonatal transfusions
quad pack
what is a massive transfusion
how much is it for an adult
what are the associated problems
transfusion that amounts to full blood volume within 24 hours
10-12 units in an adult per day
coagulopathy, hypothermia, hypocalcemia
what is the rule of thumb for massive transfusion management
1 unit FFP per every 2-3 units of RBCs
indications for donor apheresis
stem cell collection for BM transplant
indications for plasma exchange
TTP and HUS
indications for therapeutic plasma pheresis
hematological and neurological dz
indications for therapeutic RBC exchange
sickle cell
fetal and neonatal HDN
