Indicator Cells
Definition
Commercially prepared or freshly washed red cells of known ABO group used to detect antibody activity in an eluate or residual antiserum. A-positive cells detect anti-A activity; B-positive cells detect anti-B activity.
- Purpose
- Detect antibody activity in eluate or residual antiserum
- A-positive cells
- Detect anti-A activity
- B-positive cells
- Detect anti-B activity
- Source
- Commercially prepared or freshly washed red cells
Common questions
Why must indicator cells be of known ABO group before use?+
The test result is only interpretable if the reactivity of the indicator cells themselves is certain, so a known A or B group lets a positive agglutination be attributed specifically to anti-A or anti-B activity rather than to an ambiguous mixed reaction.
What happens if indicator cells are used after they have aged too long?+
Stored red cells lose antigen strength and become prone to spontaneous agglutination or haemolysis, which can produce false positive or weak results, so laboratories use freshly washed cells or commercial cells within their validated shelf life.
Related terms
- Absorption
- The purification technique in which a crude antiserum is mixed with antigen preparations from cross-reacting species. Cross-reactive antibodies bind those antigens and...
- Elution
- The release of antibody from antigen, typically by heating to 56-70 degrees Celsius. In the absorption-elution method, this step liberates the antibody...
- Inhibition Index
- A quantitative measure of PCR inhibitor burden in a DNA extract, derived from the Ct shift of an internal positive control (IPC)...
- Mixed Agglutination
- A microscopy-based technique in which indicator cells form rosette aggregates around antigen-bearing stain material via antibody bridges. Positive results are read as...
- Titre
- The concentration of antibody in a solution, expressed as the reciprocal of the highest dilution at which agglutination is still visible. A...