Clinical laboratory methods: Which of the following are recognized immunoelectrophoresis techniques used to separate and visualize antigen–antibody systems in diagnostic immunology?

Introduction / Context:
Immunoelectrophoresis combines electrophoretic separation with immunochemical detection to analyze complex antigen mixtures. It is foundational in clinical immunology for profiling serum proteins, detecting monoclonal components, and confirming antigen identity using specific antibodies.

Given Data / Assumptions:

• The question lists several named techniques and asks which are true immunoelectrophoresis methods.
• We assume standard laboratory definitions used in diagnostic serology and protein chemistry.
• “Coimmunoelectrophoresis” is not a standard, widely accepted technique name in this context.

Concept / Approach:
Classic immunoelectrophoresis variants include two-dimensional immunoelectrophoresis (separation followed by diffusion with antiserum in a second dimension) and counterimmunoelectrophoresis (antigen and antibody are electrophoresed toward each other to accelerate precipitin line formation). Both are firmly established procedures.

Step-by-Step Solution:

Verification / Alternative check:
Diagnostic manuals describe counterimmunoelectrophoresis for rapid detection (e.g., bacterial capsular antigens) and two-dimensional immunoelectrophoresis for fine protein characterization, confirming their legitimacy.

Why Other Options Are Wrong:

• Counterimmunoelectrophoresis alone: incomplete; question asks which of the following are immunoelectrophoresis techniques—more than one applies.
• Two-dimensional immunoelectrophoresis alone: same issue; not exhaustive.
• Coimmunoelectrophoresis: not a standard named technique in routine diagnostics.
• None of these: incorrect because two listed methods are genuine.

Common Pitfalls:
Confusing diffusion-only immunoassays (e.g., Ouchterlony) with electrophoresis-coupled methods; the presence of an electric field is key to immunoelectrophoresis variants.

Final Answer:
Both (a) and (b)