MLS 4140 Blood Bank LAB Exam 1

30-35%

Blood collected from a normal individual would represent what percentage of cell suspension?

100%

The appearance of the cellular portion of a centrifuged tube of blood collected in an anticoagulant represents an approximately what percentage of cell suspension?

.02 x 5.0mL = .10 mL (100 uL)

How much packed cells would you add to 5 mL of saline to create a 2% cell suspension?

.05 x 2.0 mL = .10 mL (100 uL)

How much packed RBCs would you add to 2 mL of saline to create a 5% cell suspension?

.2 mL / .05 = 4 mL saline

How much saline would you need to create a 5% cell suspension, if you only had .2 mL of packed RBCs?

(.05 mL / 2.5 mL) x 100 = 2%

What percentage of cell suspension would you create by mixing .05 mL of packed RBCs with 2.5mL of saline?

-elution techniques

-creating cell suspensions

-mechanical breakdowns

When might manual cell washing be required?

sulfosalicylic acid

SSA is also known as

Sulfosalicylic acid (SSA)

This reagent will agglutinate proteins left over in supernatant from washing RBCs

False. With each successive wash there will be fewer proteins left in the supernatant. After the 4th wash there will be little to no proteins left to react with the SSA, causing a clear solution.

SSA that is added to supernatant from RBCs that have been washed 4 times will be turbid. True/False.

6-7 times

How many times should you wash cord blood?

Direct Antiglobulin Test

What test detects in vivo sensitization of patient RBCs?

-anti-IgG

-anti-C3b (complement)

What does Polyspecific AHG contain?

Because polyspecific AHG has both IgG and complement components, monoclonal AHG helps determine which of the two are sensitizing patient cells in vivo

Why is it necessary to use monoclonal AHG after a positive DAT using polyspecific AHG?

Incubate the test and control tubes for five minutes at room temperature and centrifuge again.

What should you do if you are processing a DAT and there is no agglutination after immediate spin?

Adding 1 drop of check cells to a negative test should agglutinate after centrifugation to confirm a negative test.

How is a negative DAT test confirmed?

You must rerun the entire DAT

What should you do if check cells do not agglutinate in a DAT test?

-patient cells washed inadequately

-reagent deterioration

-reagent contaminated with serum

Why might check cells in a DAT procedure fail to agglutinate?

Monoclonal IgG AHG. Infants do not make complement.

What type of AHG should be used on infant specimens?

-EDTA

-Citrate

What type of anti-coagulents should be used for DAT specimens?

Forward reaction. Babies do not create antibodies, so reverse typing is unecessary.

How are infant ABO groups typed?

False. All reactions should occur at room temperature

Heat is sometimes applied during ABO grouping. True/False

-one drop anti-sera

-one drop unknown cells

For ABO typing, how many drops of patient cells are added to reagent sera?

-one drop reagent cells

-two drops of unknown serum

For ABO typing how many drops of unknown serum are added to reagent cells?

-repeat the test

What is the first course of action when an ABO discrepancy arises?

Dolichos biflorus

What is the source of anti-A1 lectin?

Ulex europaeus

What is the source of anti-H lectin?

cord blood

What is used as a positive control when testing patient blood for H antigen?

A blend that contains:

-monoclonal IgM anti-D

-polyclonal IgG anti-D

What composes the reagent used for detection of the Rho(D) antigen?

90%

Commercial anti-D reagents can correctly identify what percentage of all Rh-positive samples?

Indirect antiglobulin test (IAT)

What test is used to determine "weak D"

Polyclonal IgG anti-D reagent

What type of reagent is used with a "weak D" IAT?

Kleihauer-Betke test

What test should be done if an Rh negative woman tests weakly positive for D antigen, and has suffered a massive fetal-maternal hemorrhage?

Partial D mothers can develop D antibodies if exposed to the full D antigen during delivery

Why are some weak D mothers at risk for during delivery?

-When a patient types as AB+

-During weak D testing

When is a negative D control necessary during testing?

Incubate both the test tube and the control for 15-30 mins at 37C

What should be done during Rh testing if there is no agglutination after the addition of anti-D?

additional proteins in the test sample will neutralize the AHG before it has a chance to react with the sensitized cells

Why must you wash test cells after incubation at 37C before adding AHG?

Agglutination with the addition of check cells

What do you do to prove a true D negative result during D testing?

hemagglutination inhibition

What testing method is the basis for determination of the secretor property

Boiling denatures enzymes that would otherwise destroy water-soluble blood group substances

What is the purpose of boiling the supernatant of centrifuged saliva in the secretion test?

The patient is not a secretor, they do not possess the Se gene.

After adding indicator cells to a secretion study you notice agglutination. Interpret these results.