[Enzymo-immunological estimations. Principles and applications (author's transl)]

Area of Science:

• Biochemistry
• Immunology
• Analytical Chemistry

Background:

• Enzymo-immunological estimations share reaction principles with radio-immunoassays.
• Key difference lies in using enzymatic labels instead of isotopic labels on antigens or antibodies.

Purpose of the Study:

• To review the main problems and advantages/disadvantages of enzymo-immunological techniques.
• To present examples of alpha-fetoprotein estimations using different enzymo-immunological reactions.

Main Methods:

• Enzymatic label substitution for isotopic labels in immunoassay reactions.
• Measurement of enzyme activity instead of isotopic counting.
• Inclusion of substrate addition and enzyme reaction stages.
• Discussion of the EMIT (Enzyme Multiplied Immunoassay Technique) system.

Main Results:

• Enzymo-immunological techniques require additional steps for substrate addition and enzyme reaction.
• The EMIT system offers a unique approach by measuring changes in haptenised enzyme activity.
• Alpha-fetoprotein estimations using three different reactions showed similar performances.
• Major advantages include reagent stability and avoidance of isotope-related administrative controls.

Conclusions:

• Enzymo-immunological methods offer a viable alternative to radio-immunoassays.
• Reagent stability and simplified regulatory compliance are significant benefits.
• These techniques are effective for various estimations, including alpha-fetoprotein levels.