Testing for acanthocytosis A prospective reader-blinded study in movement disorder patients

Area of Science:

• Hematology
• Neurology
• Clinical Diagnostics

Background:

• Acanthocytosis in peripheral blood smears is crucial for diagnosing neuroacanthocytosis syndromes, including chorea-acanthocytosis (ChAc) and McLeod syndrome.
• Genetic testing is limited for most neuroacanthocytosis disorders, and standardized methods for quantifying acanthocytes are lacking.

Purpose of the Study:

• To establish reference values for acanthocytes in healthy volunteers and patients with movement disorders (MDs).
• To evaluate a novel method for acanthocyte detection using light microscopy, isotonic dilution, and wet preparations.

Main Methods:

• A prospective, reader-blinded study involving 100 patients with MDs, 31 with unclassified MDs, and 37 healthy controls.
• Erythrocyte morphology was assessed using light microscopy in standard EDTA and isotonically diluted blood samples, both as dry smears and unfixed wet preparations.
• Normal values were defined as the 99th percentile of combined results from healthy volunteers and patients.

Main Results:

• Isotonic dilution and wet preparations significantly increased acanthocyte detection compared to standard EDTA dry smears.
• No significant differences in acanthocyte levels were found between patients with diagnosed MDs and healthy volunteers across all conditions.
• The method using diluted blood and wet preparations demonstrated high specificity (0.98) and sensitivity, detecting all genetically confirmed ChAc patients.

Conclusions:

• A standardized method using isotonically diluted blood and unfixed wet preparations is recommended for detecting clinically relevant acanthocytosis in movement disorders.
• The recommended normal range for acanthocytes is <6.3% of total erythrocytes.
• This cost-effective and accessible method offers high diagnostic accuracy for movement disorders associated with acanthocytosis.