Blood bank rotation (Week 3)

List three reasons for a positive DAT

HDFN

Transfusion Reactions

Autoimmune hemolytic anemia

How does one perform a DAT?

1)Make a 5% suspension of patient RBC, collected in EDTA

2)Wash 4-6X

3)Add poly-specific AHG

4)Check for agglutination

5)If positive, start over with 2 tubes

6)After washing, add anti-IgG to one tube

7)Add anti-C3b complement to the other

8)Check for agglutination

9)Add check cells

There are 3 reagent sera used, what are they?

IgG

C3

Saline

What does the term "sensitized RBC" mean?

The RBC is coated in antibody

In HDN, whose antibodies coat the fetal RBC?

The mom's

Describe Kernicterus, what is the danger to the infant?

Bilirubin in the bloodstream is too great and ends up in the brain tissue

Can cause permanent neural damage

What happens in an exchange transfusion?

This replaces the neonate's blood almost entirely

At what bilirubin level would Kernicterus be feared?

(what is the critical bilirubin level)

18 mg/dl

List 4 special conditions for blood that will be used for a fetal transfusion. What is the rationale for each?

Must be compatible with Mom's antibody- use O typing

~fetus does not make antibodies, HDN is due to mom's antibodies

CMV negative

~baby cannot fight off this infection

HbS negative

~the reduced oxygen tension in utero could cause HbAS cells to sickle

Less than 7 days old

~older blood loses DPG

~Na/K pump goes down and can cause hyperkalemia

Irradiated

~kills T cells eliminating graft vs host disease

How do you do a crossmatch for newborn transfusion?

Tests the maternal serum or cord blood serum against the proposed donor unit

Why does an older unit of blood have an elevated K+?

The sodium potassium pump slows down

What does irradiation of the blood unit do to it?

Kills T cells, eliminating GVHD

What is the advantage of an exchange transfusion for the baby?

Removes sensitized cells

Removes maternal antibodies

Decreases bilirubin

Replaces incompatible RBCs

Why would it be a BAD plan to use paternal blood for transfusion in HDN?

The mom's antibodies in the baby can react to Dad's blood since the antigen on the baby's RBCs is most likely from him and foreign to the mom.

What routine tests are done on the mother after delivery?

ABO/Rh

Antibody screen

Autocontrol

Autocontrol

Patient cells are mixed with patient plasma.

You use it to rule out an autoantibody. If all 3 screening cells agglutinate, but the auto control is negative, it's a good indicator that you're dealing with an alloantibody rather than autoantibody.

What routine tests are done on the infant after delivery?

What tests are not necessary to do on the infant?

ABO/Rh

DAT

weak D

Reverse type

Antibody screen

What is the typical case scenario for ABO HDN?

O type Mom with an A or B baby

Baby usually has a positive DAT

In ABO HDN, is the Anti-A IgG or IgM?

IgM

How can you prove that HDN is caused by anti-A and not something else?

The eluate is tested against A1 cells, B cells, and screening cells.

A1 will be *positive*

B cells and screening cells

will be *negative*

Which type of HDN can cause infant cells to become spherocytes, ABO or Rh?

ABO

ABO HDN can occur during the first pregnancy.

Is this the case with Rh HDN?

It is very rare

What is antenatal Rhogam, and why is it administered? Who should receive it?

Rh immunoglobulin (RhIg)

Administered at 28 weeks gestation to prevent anti-D from developing.

Moms who are Rh negative receive it

What are the conditions that make a woman a candidate for Rhogam?

Must be Rh -, Weak D -

Must not already have anti-D

Infant is Rh +

*Dose is determined based on

Fetal-maternal bleed

Some women who received antenatal Rhogam will have an anti-D antibody after delivery.

What titer suggests that the anti-D is "passive", from Rhogam?

1:2

What is a "blocked Rh", sometimes seen on a baby's cells?

What reaction will you see on the D type and the DAT?

Blocked Rh occurs when the baby is Rh positive but so much maternal antibody is coating the baby's cells that the D reagent cannot access the D sites.

D type will be *negative*

DAT will be *positive*

The first test done to determine how much Rhogam to give a woman after delivery is to do a Fetal Maternal Bleed Screen (Rosette) Test.

If the FMBS is negative, how much Rhogam is administered?

1 vial

If the FMBS is positive, what test is reflexively ordered

Kleihauer Betke

Describe the Kleihauer Betke test.

How does it work?

Quantitative test to determine the percent of fetal cells in the mother's blood. Determines how much Rhogam to administer.

Acid elution knocks off hemoglobin, but not the fetal hemoglobin and is stained so that fetal cells retain stain. Fetal cells stain a *darker red/hot pink color*, while maternal cells stain a lighter, white-ish pink.

If the mother has hereditary persistence of fetal hemoglobin (HPFH), is the test valid? Why or why not?

The test is not credible due to the retention of fetal hemoglobin in maternal blood, all cells will be positive.

It is recommended to use another method such as flow cytometry.

One dose of Rhogam "covers" how much of a fetal bleed?

This is not the same as packed cells. What volume of packed cells is covered?

30 mL whole blood

15 mL packed RBCs

If a mom has a 1% fetal RBC in her circulation, how many vials of Rhogam should she get?

Math:

1) 1% x 5/3=1.667

2) Round up/down=2

3) add 1=3

*3 vials total*

What is the formula used to determine the # of vials of Rhogam a mom should receive?

%Fetal cells x 5/3

*Round the result and add 1 vial

What is the time limit after delivery for administration of Rhogam?

72 hours

What other antibodies can cause HDN?

Will Rhogam help prevent their formation?

Any other IgG antibody that has antigens on RBC cell surface:

~Rh

~Kell

~Duffy

~Kidd

No

HDFN will affect the baby's lab values in a specific way. Complete the chart with "increase" or "decrease".

If a patient who is pregnant has a positive antibody screen, what is the follow up in the Blood Bank?

Antibody panel(s) for ID

Complete the following serial dilution up to 1:128

*1:2 1:4 1:8 1:16 ? ? ?*

1:32 1:64 1:128

Evaluate a Lilley Graph. Which zone indicates that the fetus is in immediate danger?

Zone 3

What wavelength of light is absorbed by bilirubin?

450

Why is anti-Lea associated with pregnancy? Does it cause HDN?

It is IgM in nature, naturally occurring, and is commonly found in pregnant women.

It does not cross the placenta and fetal RBCs don't have Lewis antigens on their surface yet, so it can not cause HDN?

Does anti-P1 cause HDN?

No

Determine which mother/infant pair(s) will require Rhogam:

Mother D+/Infant D+ Mother D-/Infant D+ Mother D-/Infant D- Mother D+/Infant D-

How will this change if the mother has anti-D in her serum from a previous pregnancy?

Mother D-/Infant D+

Mother D-/Infant D-

~wouldn't need any more after delivery

When a baby is born maternal and baby blood mix, and the mom can be exposed to D and make an Anti-D, if she has a second child the anti-D she made in her previous pregnancy could attack the new fetus.

If a fetus or newborn requires a transfusion, what blood type should be chosen?

Type O

Why is it more important for the donor unit to be compatible with the mother than the infant?

Mom's blood in baby's circulation has antibodies

What if no compatible blood is found for fetus/infant, where might you look next for a donor?

The mother

A mother is Group A, D negative with anti-D. The father is Group O, D positive.

Their newborn baby has a positive DAT with 4+ agglutination, and severe anemia requiring transfusion. The baby is A, weak D positive. These results only make sense if the weak D is a false result. What's causing the false positive weak D result?

Blocked Rh

A newborn showed a strongly positive DAT. The mother's antibody as well as the antibody in the eluate prepared from this baby's cells reacted with all reagent red cells tested. The incompatibility was due to an unidentified antibody ( a private antigen to the father's cells). If the baby urgently needs a transfusion, what can be the source of the compatible blood?

The mom

In cases of severe HDN due to anti-D, the cord blood will be DAT+ but D negative.

Explain the possible reason for this reaction

Usually due to Blocked Rh caused by the baby's RBC's being overly coated in the mom's anti-D

One week prior to the date of delivery, a physician asks the blood bank to have blood on hand for an exchange transfusion.

The fetal blood type is unknown, but what is known about the mother is shown in the table below. What is the correct blood type to be selected for each mother?

The most common cause of a Transfusion reaction is "clerical error".

What 2 clerical errors are we talking about?

Incorrect identification

Mislabeling a sample

Hemolytic Transfusion reaction (TRXN) - what is the most common incompatibility that causes rapid hemolytic reaction? How does complement play a role in it?

Anti-A

K, Jka, and Fya are other less common causes

They bind complement causing positive agglutination reactions at immediate spin

Rh antibodies can cause a delayed transfusion reaction. How does that work?

Some antibodies were present and more antibodies are produced after re-exposure. Transfused cells are coated and sequestered by the spleen.

Which antibodies can fix complement and cause an intravascular TRXN?

A

K

Jka

Fya

What is the initial check done in the Blood Bank to evaluate a suspected hemolytic TRXN?

If the DAT is negative and the post-transfusion serum is not hemolyzed, what should the MLS do?

If those tests are positive, what should he do?

The clerical check of all printed materials. Compare pre-transfusion and post-transfusion tubes

Nothing

Do an elution to ID, extended workup

1. A patient received 2 units of blood after a transplant. This brought his H&H to 12 g/dL and 37%. He was discharged from the hospital. Three days later, he returns with a H7H of 7.0 g/dL and 22%. His DAT is positive. What do you suspect?

What would you do next?

TRXN

Clerical check, extended work up

Describe a febrile reaction. What is the likely cause of it?

What processing step is in place to minimize febrile reactions?

Reactions to WBCs

Use leuko-depleted RBCs

What should be done if a patient experiences urticaria during a transfusion? What antibody type is involved?

Stop transfusion and give Benadryl and then resume

Due to IgE antibodies in either donor or recipient

What type of TRXN occurs in IgA deficient patients?

Immediate non-hemolytic anaphylaxis

Bacterial contamination of a unit of blood can be deadly. Name 3 bacteria that are likely culprits.

Yersinia enterolitica

Pseudomonas

E. coli

How are potassium and calcium values changed in a patient who has received a massive transfusion?

Potassium increases and calcium decreases

Describe TRALI. What does it stand for?

Transfusion Related Acute Lung Injury

Seen within a few hours of transfusion.

Why might female derived donor components be more likely to cause TRALI?

Did you know it is the most common cause of fatal transfusion events?

Donors who have had multiple pregnancies are more likely to have antibodies assumed to cause TRALI

What is the name of the federal agency that is responsible for the safety of the nation's blood supply?

FDA

A fatal transfusion reaction must be reported to the FDA within how many days?

7 days

What are three types of immune hemolytic anemia?

Allo-immune

Autoimmune

Drug induced

Indicate the expected results for hemolytic anemia. Complete the chart with "increase" or "decrease" when the patient has hemolytic anemia

When testing a DAT, why should the sample be collected in EDTA?

This inhibits complement activation so the DAT will be positive because of IgG and not complement

Cold autoantibodies may be benign or pathologic. Anti-I interacts with all _______ cells. Anti-i interacts with _________ cells

adult

fetal

Anti-H reacts more strongly with ______ cells, and less strongly with ____ cells. This is why a patient who is A positive with anti-H will show a strong reaction with the panel cells and a weak reaction with the donor cells

O

A

Anti-H may be a benign auto-antibody. It is also found in individuals with Bombay phenotype but different. Is it okay to give H positive blood to either of these groups?

Auto-yes

Bombay-No

Describe Cold Hemagglutinin's disease

What bacterial infection may precede it?

Can be caused by an anti-I, reacts more in winter. Symptoms are hemolytic anemia

Mycoplasma or EBV

What is PCH?

It usually has the specificity of auto-anti-___?

Paroxysmal Cold Hemaglobinuria

~associated with measles

P

What is another name for the Donath Landsteiner antibody?

Anti-P

What is meant by the biphasic behavior of auto-anti-P1?

Binds to patient red cells at low temperature but won't lyse them until cells return to body temp

List the four methods that can be used to eliminate the interference of anti-I and "see underneath it".

Which one of these eliminates IgM antibodies?

Which one cannot be used if the patient has recently been transfused?

Prewarm panel

Auto-adsorption

REST adsorption

DTT

DTT

Auto-adsorption

WAIHA are usually _____ autoantibodies of the _____ blood group. A common one to find is auto-anti-____?

IgG

Rh

e

When working up a WAIHA, the MLS does a panel, and also does an elution of the +DAT. The eluate is tested against a panel as well. Is it possible that the serum panel and the eluate panel give different results?

Yes

How does one perform an autoabsorption?

Patient's RBC are tested against their own serum to allow autoantibodies to bind, the serum is then harvested, and the autoantibody is removed.

What is the advantage of doing an autoabsorption?

Removes autoantibody to assist in other antibody identification

Why should you NOT do an autoabsorption if a patient's RBC if they have been recently transfused?

The RBCs may not be the patient's or it could be an antibody detected against the donor RBCs

Name 3 treatments used to treat patients with WAIHA without transfusing them

Corticosteroids

Splenectomy

Immunosuppressant drugs that interfere with antibody production

True or false: if a patient has WAIHA, you can just ignore it because it won't lyse transfused blood.

FALSE

Complete this chart about the four types of Drug induced immune hemolytic anemia