Interactive morphometry: the influence of magnification.

The influence of magnification on light microscopic morphometry was studied. Morphometry was performed on 34 hepatocytes by using a digitizer plate with micrographs of the nuclei, and with digitized image of the nuclei on a separate monitor. Intraobserver variation was smallest at objective magnifications of 40 and 100 X (CV of form factor, maximum diameter and nuclear perimeter under 1%, of nuclear area under 2%, when measured from the monitor). The results show that more reproducible measurements are possible with higher magnifications. The authors recommend objective magnifications of 40 and 100 X for morphometric measurements on nuclei. The results also suggest that morphometric grading should apply an intermediate third grade in dichotomous grading scales.