Fixation: What should the pathologist do?

Synopsis Pathologists handling surgical material must make a definitive diagnosis, usually on a Haematoxylin-Eosin stained section, but must also consider beforehand what supporting histochemical investigations may be needed. When only one small piece of tissue is available it should either be fixed in cold neutral or buffered formalin-calcium or formalin-sucrose or alternatively quenched; the first alternative offers a more practical all-round procedure and most investigations which are likely to be of use can be done following it. If the biopsy is divisible into two, one piece should be fixed and the second quenched; if 3 pieces are available, the third should be fixed in glutaraldehyde for possible electron microscopy.     

Eminent pathologist,educator—surgeon and ethicist receive CMA honours

During the CMA''s 128th annual meeting in Winnipeg in August, 33 physicians were awarded senior membership in the association and 2 physicians and an ethicist were honoured for their outstanding contributions to medicine. Pathologist Donald Penner of Winnipeg was awarded the CMA''s highest honour, the F.N.G. Starr Award. Toronto surgeon and educator Donald Wilson received the Medal of Service, and Montreal ethicist David Roy was awarded the Medal of Honour.     

The ASCUS : SIL ratio and the reference laboratory pathologist

The atypical squamous cells of undetermined significance (ASCUS) : squamous intraepithelial lesion (SIL) ratio was proposed to monitor laboratory use of the ASCUS diagnosis. This study addresses problems associated with comparing pathologists by this means. An intuitive example showed the ASCUS : SIL ratio depends on the prevalence of smears from patients who actually have SIL. In this study of 2000 cervical smears, each of five pathologists made 400 diagnoses. Differences among proportions of SIL diagnoses were statistically significant; differences among proportions of ASCUS diagnoses were not. Had an ASCUS : SIL ratio upper limit of 3.0 been used, two pathologists would have been misidentified as having high ASCUS diagnosis rates. Unlike the situation for laboratories, potential variability in SIL prevalence requires caution in the use of this ratio in assessing pathologists. An alternative measure that is independent of prevalence, the ASCUS : SIL odds ratio, is posited.