Rocket immunodiffusion terminology: what is the alternative name for this technique? Identify the commonly used term for the Laurell rocket assay.

Introduction / Context:
Rocket immunodiffusion, developed by Laurell, is a quantitative method for antigen determination in gels. Knowing its alternate name helps link textbook descriptions to practical protocols.

Given Data / Assumptions:

• Antiserum is incorporated uniformly into agarose gel.
• An electric field drives antigen migration through the gel.
• Precipitation forms rocket-shaped arcs proportional to antigen concentration.

Concept / Approach:
Because electrophoresis drives antigen movement and precipitation, the method is accurately termed electroimmunodiffusion. The height of each “rocket” is compared against standards to quantify antigen concentration.

Step-by-Step Solution:
Recognize the role of an applied electric field in Laurell's method.Connect the principle (electrophoresis plus immunoprecipitation) to the term electroimmunodiffusion.Select the option that matches this terminology.

Verification / Alternative check:
Method descriptions explicitly state that antigen migrates under current and precipitates in the antibody-containing gel, forming rockets.

Why Other Options Are Wrong:
“Gel diffusion” is generic and includes passive Ouchterlony diffusion. “Double-diffusion” specifically refers to Ouchterlony without applied current. Isoelectric focusing is a separate protein separation technique based on pI.

Common Pitfalls:
Confusing rocket immunodiffusion with radial immunodiffusion (Mancini), which is passive and circular.

Final Answer:
Electroimmunodiffusion.