A low voltage diathermy loop for taking cervical biopsies: a qualitative comparison with punch biopsy forceps.

Twenty patients attending a colposcopy clinic because of a cytological suspicion of dyskaryosis were entered into a 'paired' biopsy study. A low voltage diathermy loop biopsy and a punch biopsy were taken from the cervix of each patient. In a second 'unpaired' study loop biopsies taken from 20 patients were compared with punch biopsies taken from 20 different patients. The length and depth of the loop biopsies were greater than those of the punch biopsies. There was no difference in the amount of artefactual damage. These findings held for both the paired and the unpaired studies. We conclude that biopsies taken with the low voltage diathermy loop are more likely to reveal microinvasive disease.