3. Blood Bank Reagents and Equipment

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What is the goal of Learning Outcome 3 in MLT 1308?

Demonstrate knowledge of blood bank reagents and tests used in routine testing.

What factors are related to blood bank reagents?

Potency and specificity.

Which reagents are commonly used for ABO testing?

Anti-A and anti-B antisera.

What is the purpose of low-protein reagent control?

To ensure accurate testing by controlling for false-positive results.

What is the difference between polyclonal and monoclonal reagents?

Polyclonal reagents bind to multiple epitopes on an antigen, while monoclonal reagents are identical antibodies targeting a single epitope.

How is potency measured in blood bank reagents?

By the strength of agglutination reported as 4+, 3+, 2+, 1+ or 0.

What indicates a negative reaction in serological agglutination?

A grade of 0.

Why should you not report negative reactions with symbols?

It may confuse the data entry and be interpreted as errors.

What affects the strength of agglutination?

Antibody concentration, reagent preservation, storage conditions, and expiration.

Why is specificity important in blood bank reagents?

To ensure that reagents react only with their intended antigens, preventing false-positive results.

What does a high specificity in reagents guarantee?

That reactions are meaningful and interpretable.

What is the function of quality control (QC) in blood bank reagents?

To verify potency and specificity, ensuring reagents meet established standards.

What is indicated if agglutination results are less than 3+?

The reagent's potency may be deteriorating.

What happens if either potency or specificity fails QC?

The reagent becomes unacceptable for patient testing.

How is forward ABO typing performed?

By adding patient red cells to known antisera (antibodies) and observing agglutination.

What does a positive agglutination reaction in ABO testing indicate?

The presence of specific antigens on red blood cells.

What is the purpose of reverse ABO typing?

To confirm forward typing by detecting the presence of antibodies.

What do anti-A and anti-B antisera do in ABO testing?

Determine the presence or absence of A or B antigens.

What is Landsteiner's Rule in blood typing?

Patients possess antibodies against the antigens they lack.

What does a positive reaction in reverse ABO testing indicate?

The presence of the corresponding antibody in patient serum.

When must an anti-D control be run?

Every time anti-D testing is conducted to prevent false positives.

What is the significance of weak subgroups in ABO blood typing?

They require additional testing to confirm results.

How is Rh typing different from ABO typing?

Rh typing checks for the presence of the D antigen, while ABO typing checks for A and B antigens.

What additional tests must be performed in Rh typing?

Rh control to ensure accurate results.

What are monoclonal antibodies derived from?

A single clone of B cell that produces identical antibodies.

How are polyclonal antibodies generated?

By immunizing an animal and harvesting the diverse IgG produced.

What is the definition of preventative maintenance in blood banking?

Routine procedures performed to keep equipment functioning correctly.

What does the serofuge do in blood banking?

Separates blood components by density using centrifugal force.

What is a common problem in automated cell washing?

Incomplete washing due to incorrect saline volume or cycle settings.

What should be done if hemolysis occurs during serofuge operation?

Reduce speed and handle specimens gently.

What must be documented in quality control logs?

Testing date, reagent name, lot number, controls used, results, and initials.

Why is proper temperature storage important for reagents?

To maintain reagent potency and prevent degradation.

What do you do if QC fails during testing?

Repeat testing with new reagents or investigate issues before releasing results.

What characteristics should be monitored for in reagent solutions?

Clarity, presence of precipitates, and expiry status.

What are pooled cells used for in reverse testing?

To confirm forward ABO typing by testing for corresponding antibodies.

What identifies a negative reaction in the Rh antigen test?

No agglutination indicates absence of the D antigen.

What is a hybridoma?

A cell line created by fusing a specific plasma cell with a myeloma cell for mass production of identical antibodies.

What type of antibodies do monoclonal products comprise?

Homogeneous antibodies targeting one specific epitope.

What can result from reagent degradation?

Weak or missing reactions during testing.

What is the main problem associated with high protein Reagents?

Increased risk of false-positive reactions.

Which antibodies develop naturally without prior exposure?

ABO antibodies.

What indicates the presence of a reagent issue in QC?

Cloudiness, unexpected positive or weak reactions.

Why should a maintenance log for blood bank equipment be maintained?

To ensure patient safety, reliability, and traceability of equipment performance.

What rehydration method should be followed for freeze-dried material?

Always rehydrate as directed by the manufacturer's instructions.

Why must, reagent cell pipette tips never touch fingers?

To prevent contamination and ensure accurate testing.

What is indicated if testing results are variable?

Possible technical errors or poor antigen expression.

What must be done if there is a discrepancy between forward and reverse ABO typing results?

Emergency procedures require type O Negative units for transfusion until resolved.

In automated washing, how many times should red cells typically be washed?

At least four times to ensure thorough cleaning.

What is a common troubleshooting step when equipment fails?

Inspect tubing for clogs or mechanical errors.