SECTION 3: IMMUNODIFFUSION/CIE

MICRO-OUCHTERLONY

Samples testing positive for ANA in IFA Test System should be further investigated for extractable nuclear antigens (ENA). ENA is a group of saline soluble macromolecules that can be extracted from various tissues - not all nuclear, some are cytoplasmic. Additional testing is needed to specifically characterise them.

PRINCIPLE

Utilising a micro-ouchterlony double diffusion test system, antigens contained in an ENA extract diffuse through agarose gel, while the patient antibodies in the surrounding wells diffuse towards the centre antigen extract well. When they meet in a zone equivalence, they form a precipitant line that can be visualised. Because the results are visual, it is easy to determine 'identity', 'partial identity' and 'non-identity' between patient sera and characterised control sera.

COUNTERIMMUNOELECTROPHORESIS (CIE)