Zeng 2005.

Study characteristics
Patient sampling	Primary objectives To evaluate the diagnostic value of examining endometrial biopsy specimens for aromatase cytochrome P450 and CA‐125 for endometriosis Study population Women undergoing laparoscopy or laparotomy for pelvic pain or infertility Selection criteria Inclusion criteria: reproductive age regular menstrual cycle; exclusion criteria: hormonal treatment for 3/12 prior reproductive age, preoperative diagnosis of uterine fibroids, adenomyosis. Study design Cross‐sectional single‐gate, prospective collection of samples
Patient characteristics and setting	Clinical presentation Infertility or pelvic pain Age Mean age 33 ± 4 years, range 26 ‐ 40 years (endometriosis), 32 ± 4 years, range 25‐39 years (controls) Number of participants enrolled 58 women Number of participants available for analysis 58 women (31 women in follicular and 27 women in luteal cycle phase) Setting Department of O&G, Third Xiangya Hospital, Central South University Place of study Changsha, China Period of study March 2003 ‐ February 2004 Language Chinese
Index tests	Index test CA‐125 in serum + P450 aromatase in endometrium Details of the index test procedure as stated Serum CA‐125 was determined by chemiluminescence assay; endometrial aromatase protein was evaluated by immunohistochemistry, 2nd generation assay (ElivisionTM plus kit), positive IHC staining indicated by presence of brown particles within the cytoplasm; sample handling or laboratory technique not described Threshold for positive result CA‐125 >35 U/ml, not pre‐specified; P450 aromatase: positive or negative test Examiners No information provided, unclear if blinded to the result of reference standard Interobserver variability Not stated
Target condition and reference standard(s)	Target condition Endometriosis Prevalence of target condition in the sample n = 36/58 (62%): stage I‐II 20, stage III‐IV 16; controls n = 22 Reference standard Laparoscopy/Laparotomy n = 58 (100%) Description of positive case definition by reference standard test as reported Visual inspection; staging according to rAFS classification Examiners Not stated
Flow and timing	Time interval between index test and reference standard Blood and endometrial samples were collected on the day of surgery Withdrawals None
Comparative
Key conclusions by the authors	The combination assay of aromatase cytochrome P450 in eutopic endometrium and CA‐125 can be used as a diagnostic test for endometriosis, especially for the early stage of endometriosis, which is superior to the assay of CA‐125
Conflict of interest	Not reported
Notes	Translated from Chinese, some information may have been misinterpreted The reported diagnostic estimates for endometrial or blood markers alone are presented in other reviews from this series
Methodological quality
Item	Authors' judgement	Risk of bias	Applicability concerns
DOMAIN 1: Patient Selection
Was a consecutive or random sample of patients enrolled?	Unclear
Did the study avoid inappropriate exclusions?	Yes
Was a 'two‐gate' design avoided?	Yes
		Unclear	Low
DOMAIN 2: Index Test All tests
Were the index test results interpreted without knowledge of the results of the reference standard?	Unclear
If a threshold was used, was it pre‐specified?	No
Was a cycle phase considered in interpretation of the result of index test?	Unclear
Did the study provide a clear pre‐specified definition of what was considered to be a positive result of index test?
Was the index test performed by a single operator or interpreted by consensus in a joint session?
Were the same clinical data available when the index test results were interpreted as would be available when the test is used in practice?
		High	Unclear
DOMAIN 3: Reference Standard
Is the reference standards likely to correctly classify the target condition?	Unclear
Were the reference standard results interpreted without knowledge of the results of the index tests?	Yes
		Unclear	Low
DOMAIN 4: Flow and Timing
Was there an appropriate interval between index test and reference standard?	Yes
Did all patients receive the same reference standard?	Yes
Were all patients included in the analysis?	Yes
		Low

(r)AFS: (revised) American Fertility Society; (r)ASRM: (revised) American Society for Reproductive Medicine; CA‐125: cancer antigen; CV: coefficient of variation; DIE: deep infiltrating endometriosis; ECD: Electron Coupled Dye; ELISA: enzyme‐linked immunosorbent assay; FITC: fluorescein isothiocyanate; GnRH: gonadotropin‐releasing hormone; IL: interleukin; IUD: intrauterine device; LMP: last menstrual period; NNE: non neuronal enolase;PE: phycoerythrin; PerCP: peridinin; chlorophyll protein; PGP: permeability glycoprotein; POD: pouch of Douglas; PV: per vaginam; RVS: rectovaginal septum; TVS: transvaginal sonography; TVUS: transvaginal ultrasound; USL: uterosacral ligament; VAS: visual analogue scale; VDBP: vitamin‐D‐binding protein; VDBPCr: VDBP level corrected for creatinine.