22 - immunohematology

7/23/2019 22 - Immunohematology

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[email protected] || 1stsemester, AY 2011-2012

22 - Immunohematology

Pre-Transfusion Tests

Genetic Control of the ABO Blood Group Antigens

GENES PRESENT TRANSFERASE PRODUCED TERMINAL SUGAR RBC PHENOTYPE

HH or Hh Fucosyltransferase Fucose O

HH or Hh and A Fucosyltransferase, N-

acetylgalactosaminyltransferase

Fucose, N-acetylgalactosamine A

HH or Hh and B Fucosyltransferase, D-galactosyltransferase Fucose, galactose B

HH or Hh and A plus B Fucosyltransferase, N-

acetylgalactosaminyltransferase

D-galactosyltransferase

Fucose, N-

acetylgalactosamine, D-

galactose

AB

hh, or hh and any other

gene (A and/or B)

None, or N-acetylgalactosaminyltransferase and/or

D-galactosyltransferase

None Bombay

Gal added to the subterminal Gal confers B activity; GalNAc

added to theh subterminal Gal confers A activity to the sugar.

Unless the fucose moiety that determines H activity is attached

to the number 2 carbon, galactose does not accept either sugar

on the number 3 carbon.

Applications of Blood Group Serology

Blood grouping of donors and patients

Provision of blood for patients

Exclusion of paternity

Criminal investigations

Recipients Red Cells Plus

ABO Group Anti-A Anti-B Anti-AB

A ++++ - ++++

B - ++++ ++++

AB ++++ ++++ ++++

Subgroups A or B - - ++

PATIENTS SERUM plusABO GROUP A RBCs B RBCs

A - ++++

B ++++ -

AB - -

O ++++ ++++

Recipients ABO

Blood Group

Acceptable ABO

Blood Group of

Donor Red Cells

Acceptable ABO

Blood Group of

Donor Plasma

A A,O A, AB

B B,O B, AB

AB AB,A,B,O ABO O O, A, B, AB


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Antibody Screen

Same procedure as the crossmatch but substituting

Group O red cells phenotyped for multiple antigens

INTERPRETATION OF COMPATIBILITY TESTS

Agglutination Cause of

Agglutination

Compatible

for

Transfusion

Antibody

Screen

Crossmatch

+ - Antibody screen

with antigen on

screening cells

but not on donor

cells

Possibly

(phenotyped

donor to

confirm

compatibiltiy)

- + Antibody reacts

with a low

incidence antigen

Donor cells have a

positive DAT

Technical error -

repeat

+ + Antibody reacts

with an antigen

on donor cells

and screening

cells


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Coombs/Antiglobulin Test

DAT Use

Diagnosis of:

Hemolytic disease of newborn

Autoimmune hemolytic anemia

Drug-induced hemolytic anemia

Transfusion reactions

IAT Use

Antibody screening

Phenotyping

Cross-matching

Blood Components

Blood: 6% -8% of body weight

Plasma

Components Relative

Amounts

Function

Plasma Portion (50%-60% of total volume):1.Water 91% - 92%

of plasma

volume

Solvent

2.

Plasma proteins

(albumin, globulins,

fibrinogen, etc.)

7% - 8% Defense, clotting,

lipid transport, roles

in ECF volume, etc.

3.Ions, sugars, lipids,

amino acids,

hormones, vitamins,

dissolved gases

1% - 2% Roles in ECF

volume, pH, etc.

Cellular Portion(40% - 50% of total volume):

1.Red blood cells 4,800,000 -

5,400,000

per milliliter

Oxygen, carbon

dioxide transport

2.White blood cells:

Neutrophils

Lymphocytes

Monocytes

(macrophages)

Eosinophils

Basophils

3,000 -

6,750

1,000 -

2,700

150 - 720

100 - 360

25 - 90

Phagocytosis

Immunity

Phagocytosis

Roles in

inflammatory

response, immunity

Roles in

inflammatory

response, immunity

3.

Platelets 250,000 -

300,000

Roles in clotting

Principle 1:

The cause of the deficiency should be identified.

Principle 2:

Only the deficient component should be replaced.

Blood Components

Oxygen Carrying Components

Red cell concentrates

Leukocyte-poor blood Frozen-thawed red cells

Platelet Products

Platelet rich plasma (PRP)

Platelet concentrates (PC)

Plasma Products

Fresh frozen plasma (FFP)

Frozen plasma (FP)

Cryoprecipitate

Stored plasma


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Principle 3:

The blood product should be as safe as possible.

Blood Constituent Type of Transfusion Reaction

Red cells Acute hemolytic transfusion reaction

Delayed transfusion reaction

Transfusion of red cell alloantibodies

(passive alloimmunization)

Alloimmunization

White cells Febrile transfusion reaction

Leuokagglutinin-associated pulmonary

edema

Alloimmunization

Platelets Alloimmunization

Post transfusion purpura

Leukopenia

Plasma proteins Urticaria

Anaphylaxis

Other Graft-versus-host disease (GVHD)

Whole Blood (WB)

Composition: RBCs (approx. Hct 40%); WBCs;

platelets; plasma

Volume: 500 mL

Use: Increase both red cell mass and plasma volume

(WBCs and platelets not functional; plasma deficient

in labile clotting Factors V and VIII) Storage Temperature: 1-6C

Shelf Life: CPDA-1 = 35 days

Quality Control:

1. Donor Hemoglobin 12.5 g/dL

2. Volume = 450 mL + 10%

Clinical Indications:

WB 1. Active bleeding with at least one of the following:

a. Loss of over 15% blood volume

b. Hgb less than 9 g/dL

c. Blood pressure decrease over 20 mm Hg

and/or less than 90 mm Hg systolicWB 2. Pre-operative patients with expected blood loss

of more than 25% blood volume

Packed Red Blood Cells (PRBC)

Composition: RBCs (approx. Hct 75%); reduced

plasma; WBCs and platelets

Volume: 250 mL

Use: Increase red cell mass in symptomatic anemia

(WBCs and platelets not functional)

Storage Temperature: 1-6C

Shelf life:

1. CPDA 1 (close system) = 35 days

2. CPDA 1 (open system) = 24 hours

Quality Control:

1. Volume of red cells (4 per month) > 170 mL

2.

Hct (4 per month)< 70%(mean); never > 80%


R 1 Hgb less than 8 gm/dL or Hct less than 24% (if not due

to treatable cause)

R 2 Pre-operative patients with:

a. Hgb less than 8 g/dL or Hct less than 24%

b. Major bloodletting operation and Hgb less

than 10/dL or Hct less than 30%

c. Signs of inadequate oxygen-carrying

capacity (symptomatic anemia)

R 3 Symptomatic anemia regardless of Hgb level

(dyspnea, syncope, postural hypotension,tachycardia, chest pains, TIA)

R 4 Hgb less than 10 g/dL or Hct less than 30% in patients

with COPD, CAD, hemoglobinopathy, sepsis, aortic

stenosis and cerebral infarct

R 5 Blood loss of less than 10% blood volume


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Washed Red Blood Cells

Composition: RBCs(approx. Hct 75%);

< 5 x 108 WBCs; no plasma

Volume: 180 mL

Use: Increase red cell mass; reduce risk of allergic

reactions to plasma proteins

Storage Temperature: 1-6C Shelf life: 24 hours

Quality Control: same as PRBC (prior to washing)


WP 1 History of previous severe allergic transfusion

reactions or anaphylactoid reaction in

immunocompromised patients

WP 2 Transfusion of group O blood during emergencies

when the specific blood is not immediately available

WP 3 Paroxysmal nocturnal hemoglobinuria

Leuko-Reduced RBCs(LR-RBCs)

Prepared by filtration

Composition: > 85% original volume of RBC;

< 5 X 106WBCs; few platelets; minimal plasma

Volume: 225 ml

Uses: Increase red cell mass; 5.5 X 1010

/unit); RBCs; WBCs;

plasma

Volume: 50 mL

Use: Stop bleeding due to thrombocytopenia or

thrombocytopathy

Storage Temperature: 20 - 24C Shelf life:

1. CPDA- 1 (close system) = 5 days

2. CPDA-1 (open system) = 24 hours

Quality Control:

1. pH (4 per month) = never < 6.0

2. Platelet count (4 per month) = 5.5 X 1010

(75% or more)

3. Plasma volume (4 per month) = 45 65 mL


P-1 Prophylactic administration with count 20,000 and

not due to TTP, ITP, HUS

P-2 Active bleeding with count 50,000

P-3 Platelet count 50,000 and patient to undergo

invasive procedure within 8 hours

P-4 Platelet count 100,000 if surgery in on critical area

(e.g. eye, brain, etc.)

P-5 Massive transfusion with diffuse microvascular

bleeding and no time to obtain platelet count

Leuko-Reduced Platelets (LRPs) Prepared by Filtration

Composition: Platelets (>5.5 X 1010

/unit); RBCs;

WBCs < 5 x 106WBCs; plasma

Volume: 50 ml Uses: Same as Platelets; 3 X 1011

/unit); RBCs; WBCs; plasma

Volume: 300 ml

Uses: Same as Platelets; sometimes HLA- matched

Storage Temperature: 20-24

Shelf life: 1. CPDA-1 (close system) = 5 days

Quality Control:1. pH (4/month) = not < 6.0

2. Platelet count (4/month) = 3 X 1011

(mean)

Clinical Indications:Same as PC


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Fresh Frozen Plasma (FFP)

Composition: Plasma with all coagulation factors

Volume: 200-250 ml

Uses:

1. Provide all coagulation factors in deficiency

states

2. Plasma expander

Storage Temperature: (-) 30C or lower

Shelf life: 12 months

Quality Control: Volume (every unit) = 235 ml (mean)


F-1 PT or PTT > 1.5 times mid-normal range within 8

hours of transfusion (PT > 17 sec., PTT > 47 sec)

F-2 Specific factor deficiencies not treatable with

cryoprecipitate

F-3 Reversal of coumadin anticoagulant in patients who

are bleeding and not treatable with vitamin K

F-4 Treatment of TTP

F-5 Patient undergoing an invasive procedure with PT of

less than 70% and /or PTT of more than 44 seconds

F-6 Clinical coagulopathy associated with:

Massive transfusion ( 10 units of blood in

24 hours)

Late pregnancy termination or abruptio

placentae

Cryoprecipitate (CP)

Composition: Plasma with Fibrinogen; Factors VIII and

XIII; von Willebrand Factor

Volume: 15-20 ml

Uses:

1. Provide fibrinogen, Factors VIII and XIII and

Willebrand Factor in deficiency states, e.g.

Hemophilia A, Willebrands Disease

2. Topical Fibrin glue

Storage Temperature: (-) 30C or lower

Shelf life: 12 months

Quality Control: Factor VIII (4/month) = 80 IU (mean)


C-1 Significant hypofibrinogenemia (100 mg/dL)

C-2 Hemophilia A

C-3 Von Willebrands disease or uremic bleeding with

prolonged bleeding time

Recommendations

RBC Products

Transfusion of blood products on a unit-to-

unit basis is encouraged

A thorough clinical re-evaluation should be

made before the next transfusion

A representative post-transfusion

Hemoglobin and Hematocrit determination

could be made at least after 24 hours

Platelet Concentrate

A representative post-transfusion platelet

count could be made at least after one(1)

hour.

Cryoprecipitate and fresh frozen plasma

A more accurate post-transfusion PT and/or

PTT could be done at least after four (4)

hours.

22 - immunohematology

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