Reference intervals for feline cerebrospinal fluid: cell counts and cytologic features

Area of Science:

• Veterinary Neurology
• Comparative Pathology
• Clinical Pathology

Background:

• Accurate reference intervals for feline cerebrospinal fluid (CSF) analysis are essential for diagnosing neurological diseases.
• Previous studies have lacked comprehensive data on CSF cell counts and cytologic variables in healthy adult cats.

Purpose of the Study:

• To determine reference intervals for feline CSF cell counts and cytologic variables in clinically healthy adult cats.
• To establish reliable diagnostic benchmarks for feline neurological conditions.

Main Methods:

• Analysis of CSF samples from 58 adult cats with normal neurologic examinations and no CNS lesions.
• Evaluation of total white blood cell (WBC) count, differential cell percentages (neutrophils, eosinophils), and red blood cell (RBC) counts.
• Statistical analysis to assess the influence of age, gender, and correlation with blood values.

Main Results:

• No significant effect of age or gender on CSF variables was observed.
• No significant correlation was found between CSF variables and corresponding blood values.
• Total WBC count, neutrophil, and eosinophil percentages were positively correlated with CSF RBC count, necessitating specific reference intervals based on RBC levels.

Conclusions:

• Proposed reference intervals for feline CSF were derived, with specific considerations for samples containing low to moderate RBC counts (less than 31 cells/µL and 31–1,700 RBC/µL).
• Spinal needle gauge (20- or 22-gauge) did not significantly affect erythrocyte counts in collected CSF samples.
• These established reference intervals will aid in the accurate interpretation of feline CSF analyses for improved veterinary neurological diagnostics.