An evaluation of cellularity in various types of bone marrow specimens.

Comparisons of marrow cellularity determinations in needle biopsy sections, aspirated smears of marrow particles, and aspirated clot sections were made using the point-counting and standard visual methods of measurement. Good correlations of cellularity between biopsies and smears were obtained with the point-counting method. This occurred with either single- or multiple-observer measurements, and differed from the wide observer-to-observer variation obtained in the other comparisons. Although the optimal method for cellularity measurements is point counting by biopsy sections, the findings indicate that aspirated smears of marrow particles can be a suitable substitute for needle biopsy sections when point counting is used. This would be particularly useful in clinical settings necessitating frequent cellularity assessments. The results also show that the standard visual method of cellularity measurement is satisfactory when specimens are evaluated by one observer. The point-counting method of measurement, although the most accurate, is not as reproducible among observers as previously considered.