举个例子说一下为什么医院的基因检测相当贵

贵的原因在于准确度高，例如微基因的芯片测乳腺癌灵敏度特异性很低，你看看医学基因检测的方法：

BreastNext analyzes 17 genes (listed above). All genes are evaluated by next generation sequencing (NGS) or Sanger sequencing of all coding domains, and well into the flanking 5’ and 3’ ends of all the introns and untranslated regions. In addition, sequencing of the promoter region is performed for PTEN (c.-1300 to c.-745). The BRCA2 Portuguese founder mutation, c.156_157insAlu (also known as 384insAlu) is detected by NGS and confirmed by PCR and agarose gel electrophoresis. Clinically significant intronic findings beyond 5 base pairs are always reported. Intronic variants of unknown or unlikely clinical significance are not reported beyond 5 base pairs from the splice junction. Additional Sanger sequencing is performed for any regions missing or with insufficient read depth coverage for reliable heterozygous variant detection. single nucleotide variant calls not satisfying 100x depth of coverage and 40% het ratio thresholds are verified by Sanger sequencing.1 Gross deletion/duplication analysis for the covered exons and untranslated regions of all 17 genes is performed using read-depth from NGS data with confirmatory multiplex ligation-dependent probe amplification (MLPA) and/or targeted chromosomal microarray.

二代测序深度要至少100x，部分需要sanger测序和其他技术再次验证。