Required section · Section 3 of 6

Use visible features and artifact checks

An acanthocyte has a few irregular, unevenly spaced projections. An echinocyte has many short, evenly distributed projections; each projection is distinct from a crenated edge. These comparisons are text-based criteria for review, not a recognition exercise from an image.

A qualifying schistocyte is a small RBC fragment with sharp angles and straight borders. A helmet cell qualifies when a concave missing segment forms its helmet contour; a keratocyte qualifies when two horn-like projections define the fragment. Do not count a bite cell, crenated cell, microspherocyte, or nonspecific poikilocyte as a schistocyte. A distorted cell without these criteria is excluded.

Review distribution and artifact before naming or interpreting a form. A diffuse supported bite or blister pattern with oxidative-injury context warrants the authorized oxidative review; a field-limited crenated pattern warrants preparation review or repeat smear. Romanowsky stain supports morphology; supravital staining demonstrates Heinz bodies in vitro.

Text comparison lists acanthocyte as few uneven projections, echinocyte as many regular projections, spherocyte as dense without central pallor, and target cell as center, pale ring, and rim. — Figure 1Text-based feature comparison; not a recognition image.

Sequence diagram shows oxidative stress, Heinz-body demonstration by supravital stain, a blister cell with a hemoglobin-poor area, and a bite cell with a peripheral defect. — Figure 2Oxidative-injury sequence; use a separate supravital stain to demonstrate Heinz bodies.

Knowledge checks

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Knowledge check 1

Which feature favors an echinocyte over an acanthocyte?

Choose one option.

Numerous short, regularly spaced projections.

A few uneven projections of varied size.

Absent central pallor.

Knowledge check 2

A diffuse spiculated pattern appears in well-stained systematic fields. Which decisions are required before reporting it? Select all that apply.

Choose at least 3 options.

Review collection-to-film timing.

Assess the optimal monolayer and distribution across fields.

Consider repeat preparation when drying or aging is plausible.

Release an acanthocytosis diagnosis from the projections.

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