3. Blood Bank Reagents and Equipment

What does potency refer to in the context of blood bank reagents?

The strength of a reagent, indicating how strongly it reacts with its corresponding antigen or antibody.

How is potency in serological agglutination reported?

Measured and reported as 4+, 3+, 2+, 1+ for positive reactions and 0 for negative.

What is the significance of specificity in blood bank reagents?

The ability of a reagent to react only with its intended antigen or antibody.

Give an example of specificity in blood bank reagents.

Anti-A antisera should NOT agglutinate B antigens.

What are the two critical parameters verified by quality control of reagents?

Potency and specificity.

What does regular quality control verify?

That reagents meet minimum reactivity standards set by manufacturers and regulatory bodies.

What does the anti-A reagent test for in ABO testing?

The presence or absence of A antigens on patient or donor red blood cells.

What is the purpose of low-protein reagent control?

To check false positive results that may occur with high protein anti-D anti-sera.

What is the common method of performing ABO forward typing?

Add patient red cells to known anti-A and anti-B sera, then spin and read for agglutination.

What happens in reverse typing in blood bank testing?

Determines which ABO antibodies are present in patient serum based on the antigens on red cells.

When is reverse ABO testing commonly performed?

To confirm forward typing results.

What type of antibodies are primarily examined in reverse ABO testing?

ABO antibodies mainly IgM, which react best at room temperature or colder.

What are pooled cells used for in reverse testing?

To confirm forward typing of patient’s cells.

What does Landsteiner's Rule state regarding blood type antigens and antibodies?

Individuals possess antibodies against antigens that are lacking on their red cells.

What type of testing indicates Rh typing?

The presence or absence of the D antigen.

What type of reaction indicates that the D antigen is present in Rh typing?

Agglutination when patient RBCs are mixed with anti-D serum.

What is a critical error that could occur if agglutination is seen in Rh control?

An invalid result for Rh typing.

What is the difference between polyclonal and monoclonal antibodies?

Polyclonal antibodies are a collection from different B cells, while monoclonal antibodies are identical from a single B cell clone.

What are the primary characteristics of monoclonal antibodies?

They are identical antibodies produced from a single clone with the same specificity.

How are hybridomas created in monoclonal antibody production?

By fusing a specific B cell with a myeloma cell.

What is the purpose of quality control documentation in blood banking?

Ensures traceability and confirms reagents performed as expected.

What is an example of a common QC problem in blood banking?

Weak or missing reactions indicating reagent degradation.

What is a recommended action if quality control fails?

Repeat with new reagent or cells and document the action taken.

What should be documented in a QC log?

Date, reagent name, lot number, expiry date, tests performed, and results observed.

What is required when preparing reagents or cell suspensions?

They must equilibrate to room temperature before use.

What type of maintenance is performed on automated cell washers?

Daily cleaning, inspection, and checks of saline and waste reservoirs.

Why must saline-based reagents be used in certain tests?

They can test cells already coated with IgG antibodies.

What does preventative maintenance of serofuges include?

Daily cleaning and inspection of moving parts.

What evidence may indicate reagent red cell deterioration?

Spontaneous agglutination, significant hemolysis, or loss of agglutination strength.

What might cloudiness in an antisera indicate?

Contamination or that the reagent has been frozen improperly.

What is a critical factor in verifying reagents before use?

Ensuring that the labels are readable and that the reagents are in date.

What does the documentation during quality control support?

Patient safety by verifying test reliability.

What should be done if an unwanted reaction is noted during a test?

The reagent should not be used and corrective action should be taken.

What is the importance of temperature control during reagent storage?

Maintains potency and effectiveness of the reagents.

How do automated cell washers contribute to testing accuracy?

They remove residual plasma to prevent false negative results.

When is Rh control required in Rh antigen typing?

Must be run in parallel with anti-D if the patient is blood type AB.

What does a negative agglutination result indicate in Rh typing?

Absence of the D antigen.

What do commercial pooled cells assist with in testing?

Enhances detection of antibodies in patients, preventing false negatives.

What is the main distinguishing feature of monoclonal antibodies?

They are produced from a single plasma cell lineage, ensuring uniformity.

Why are low-protein and chemically modified reagents used in blood banking?

To reduce false-positive reactions caused by high protein reagents.

What should always be checked after maintenance actions in blood banking?

Operational status and maintenance log for compliance to protocols.