OBJECTIVETo analyze the results of prenatal karyotype of the external quality assessment program in 2013 in order to provide references and recommendations for improving the capability and performances of karyotype analysis of prenatal screening laboratories.

METHODSFive lots of quality control cell photos were sent to 500 laboratories. The participants were asked to decide whether the photos have demonstrated any abnormal karyotype and determine the abnormal type. The results should be submitted before the deadline and compared with the standard results to evaluate the performances of the laboratory.

RESULTSOne hundred forty three laboratories have returned their karyotype results for the survey. The standard answers were 7,XX,+18, 46,X,i(X)(q10), 46,XY,i(21)(q10) or 46,XY,+21,der(21;21)(q10;q10), 46,XY and 47,XY,+21 in sequential order, which were used to estimate the score of each participant. The pass rates for five lots were 97.9%, 97.2%, 95.8%, 100.0% and 97.9%, respectively. The total pass rate was 97.7%. The error rates were 2.1%, 2.8%, 4.2%, 0 and 2.1%, respectively. The total error rate was 2.3%.

CONCLUSIONSome laboratories did not correctly identify the abnormal karyotypes, while some could not determine the right type of karyotype. The external quality assessment program of prenatal diagnosis of karyotype analysis should be conducted annually in order to improve the capability and performances of karyotype analysis of prenatal screening laboratories.