LatticeMLS
Menu
Module overview
Section 2 of 6 · Open sections

Required section · Section 2 of 6

What each method separates

Cation-exchange HPLC separates fractions by chromatographic retention and reports relative peak areas. Its retention windows and assignments are specific to the declared analyzer, reagent, and software.

Electrophoresis separates hemoglobins by mobility. Alkaline electrophoresis can place Hb S and Hb D together; acid electrophoresis can separate that specific pair, but does not make every band uniquely identifiable.

Isoelectric focusing (IEF) separates hemoglobins by isoelectric point in a pH gradient. Capillary electrophoresis (CE) separates by electrophoretic mobility into method-specific zones. Each supplies separation evidence, not globin-gene sequence.

Molecular methods detect defined globin-gene sequence variants or copy-number changes. They can resolve an inconclusive phenotype when the selected assay covers the relevant change; sequencing alone may miss a large deletion or duplication. No one method erases the limitations of the others.

Quantitation is method output rather than a genotype statement. Reduced beta-chain production leaves a relatively greater proportion of delta-chain HbA2, so HbA2 can increase in beta-thalassemia carrier patterns. For example, co-inherited alpha-thalassemia can leave marked microcytosis with a non-diagnostic separation pattern; persistent microcytosis then follows the local molecular-referral pathway rather than being assigned from the fraction pattern.

Illustrative drawing — this picture was drawn rather than captured.

Four labeled panels compare electrophoresis, HPLC, capillary electrophoresis and IEF, and molecular methods by measured property, output, and principal limitation.
Figure 1Major hemoglobin methods produce different separation evidence from the same specimen.

A reusable method-to-claim model for fraction review.

  1. Name the signal

    Record whether the observed evidence is a band, retention window, migration zone, isoelectric focus, or molecular target.

  2. Name the method limit

    Check whether co-migration, co-elution, assay coverage, or quantitation interference could leave more than one explanation.

  3. Add context

    Review age, CBC indices, and available transfusion, transplant, or therapy history.

  4. Choose the next evidence

    Use a complementary separation or targeted molecular method when the pattern remains unresolved or consequential.

Knowledge checks

Reading and checks are open. Sign in only to save.

Knowledge check 1

Which pairings correctly match a method with the property it separates?

Choose at least 2 options.

Knowledge check 2

Why can acid electrophoresis be useful after an alkaline electrophoresis pattern?

Choose one option.

Section status

Finish this section

Reading and checks are open. Sign in only to save.

The module finishes after every required section is marked done and every check in those sections is correct.