Harr Clinical Chemistry Practice Test 2026 – All-in-One Study Guide for Exam Success!

Immunofixation electrophoresis (IEF) is a technique used to separate and identify specific proteins in serum or other bodily fluids, particularly immunoglobulins. The correct statement captures the essence of this method. Initially, proteins in the sample are separated by electrophoresis based on their size and charge. Following this separation, a layer of monospecific anti-immunoglobulins is applied to the gel. These antibodies react specifically with the proteins of interest, which allows for the identification and visualization of those proteins that are present in the sample.

This two-step process—separation followed by immunofixation—enables the detection of abnormal immunoglobulin production, such as monoclonal gammopathies, and helps in diagnosing conditions like multiple myeloma or other plasma cell disorders. The specificity of the antibodies plays a crucial role in this technique, as different antisera can be used to target particular classes of immunoglobulins or other proteins.

The incorrect options do not accurately represent the IEF methodology. For instance, the second choice suggests that proteins interact with antisera before electrophoresis, which would impede proper separation due to aggregation. The third option implies a design where antisera are electrophoresed, which is not