Comparison of light and transmission electron microscopy for the evaluation of body cavity effusions.

Evaluation of 282 body cavity effusions by both light and transmission electron microscopy showed that the two methods compare favorably. The major advantages of electron microscopy are higher rates of unequivocally positive diagnoses, improved diagnosis in borderline or suspicious cases and better discrimination between benign and malignant fluids or decreased numbers of inconclusive results. This was obtained without false-positive results. The major disadvantage of the method is the increased time and preparative procedures needed. As with light microscopy, the false-negative rate was high.