Quality aspects of prenatal cytogenetic diagnosis: determining the effect of various factors involved in handling amniotic fluid and chorionic villus material for cytogenetic diagnosis.

OBJECTIVES

To investigate the effect of factors involved in cell culturing and slide preparation of amniotic fluid (AF) and chorionic villus biopsies (CVB) for prenatal cytogenetic diagnosis.

METHODS

The effect on the outcome of our standard AF cell culture procedure of volume and appearance of the submitted AF specimen, gynaecologist performing the amniocentesis, week of gestation in which the specimen was taken and culture medium was retrospectively investigated. In a prospective study controlled experimental variation was introduced in composition of fixative, relative humidity, temperature and airflow during slide preparation from primary CVB and AF in situ cultures. For evaluation, analysis of regression or variance was used.

RESULTS

Provided that at least 0.8 mL AF per culture dish was admitted, none of the investigated factors appeared as critical resulting in unacceptable variation in outcome. Variation in appearance of the AF had a relatively major impact: bloody or brown AF resulted in a 3 days longer culture time. To a limited degree, metaphase quality of AF and CVB cells was affected by composition of fixative, relative humidity, ambient temperature and airflow during slide preparation.

CONCLUSION

Current prenatal cytogenetic practice as described here appears in general to be robust and reliable. The investigated conditions are not critical within the investigated range. Expensive measures for fine control of these conditions are, therefore, not required.