Fetal Tissue Procurement for Karyotype Analysis: Clinician or Pathologist - Which is Better?

Chromosomal abnormalities are detected in up to 13% of stillbirths and over 20% of those with developmental anomalies. These estimates may be low since up to 50% of samples fail to achieve a result due to microbial overgrowth or nonviability. Tissue for cytogenetics can be procured at bedside by the clinician or by the pathologist in the laboratory. With clinical collection, tissue is placed into culture media immediately, increasing chances of growth. However, collection competes for attention with other activities, which may result in microbial overgrowth or selection of maternal rather than fetal tissue. Laboratory procurement occurs in a controlled environment using sterile technique, but delay in collection may decrease viability. Our goal was to determine which collection method yields better results.

We reviewed cases from 2007-2013 that had two samples submitted for cytogenetics, one from the clinician and one from the pathologist. Specimen source, delivery, collection, and culture setup times, harvest date, cell growth, microbial overgrowth, maternal contamination and final result were obtained from medical records and cytogenetic culture sheets.

There was no difference in growth rate, maternal cell contamination, or reporting time between clinician- and pathologist-procured samples despite delay in collection time for laboratory samples. Clinical samples had more microbial overgrowth. Compared to samples collected at bedside, samples collected in the laboratory had a lower rate of microbial contamination with similar growth and maternal cell contamination rates, despite prolonged time to collection. Collecting samples both at bedside and in the laboratory is unnecessary.