SDC1 and cholesteryl ester measurement: Using endometrial biopsy and fluid collected in 7 days following luteinizing hormone surge and next-generation sequencing of 16S rRNA gene (V4 region), Liu et al. [71] investigated the local microbiota in 13 infertile women with CE, defined as the presence of more than 5.15 CD138(+) ESPCs/10 mm2 in the endometrial tissue, and 117 counterparts without CE who reside in the Hong Kong area.