Zhang 2006b.

Study characteristics
Patient sampling	Primary objective: to investigate the levels of soluble intracellular adhesion molecule‐1 (sICAM‐1) in serum and peritoneal fluid of patients with or without endometriosis, and to discuss the clinical significance of serum sICAM‐1 in pelvic endometriosis Participants: women who underwent surgical treatment for endometriosis or for benign epithelial ovarian tumours Selection criteria: exclusion criteria: steroid treatment 3 months prior to surgery, pelvic inflammatory disorder, autoimmune disease, other known internal medicine or surgical disease Study design: cross‐sectional, two‐gate design, prospective collection of samples
Patient characteristics and setting	Clinical presentation: endometriosis group ‐ not specified; controls ‐ benign ovarian mass Age: mean age 38.7 ± 9.5 years (endometriosis group), 36.0 ± 8.6 years (controls) Number of participants enrolled: 60 participants Number of participants available for analysis: 60 participants (cycle phase not reported) Setting: Department of O&G, Renmin Hospital of Wuhan University Place of study: Wuhan, China Period of study: September 2004 ‐ March 2005 Language: Chinese
Index tests	Index test: sICAM‐1 Details of the index test procedure as stated: serum sICAM‐1 was measured with human sICAM‐1 enzyme‐linked immunosorbent assay (ELISA) (R&D Systems Germany), working assay range or minimal detection limit were not reported; sample handling described Threshold for positive result: cut‐off threshold > 241.46 µg/ml, not pre‐specified Examiners: no information provided; unclear if blinded to the result of reference standard Interobserver variability: not reported
Target condition and reference standard(s)	Target condition: endometriosis Prevalence of target condition in the sample: n = 30/60 (50%): stage I‐II 14, stage III‐IV 16; controls n = 30 Reference standard: laparoscopy/laparotomy N = 60 (100%) + histology Description of positive case definition by reference standard test as reported: visual inspection confirmed by histopathology; staging according to the rASRM classification Examiners: no information provided
Flow and timing	Time interval between index test and reference standard: blood samples were collected on the day of surgery Withdrawals: none
Comparative
Key conclusions by the authors	The sICAM‐1 may participate in the inflammatory process in endometriosis. Serum concentrations of sICAM‐1 seem to be the effective indicator for the diagnosis of endometriosis.
Conflict of interest	Not reported
Notes	The data for markers measured in peritoneal fluid are not reported in this review
Methodological quality
Item	Authors' judgement	Risk of bias	Applicability concerns
DOMAIN 1: Patient Selection
Was a consecutive or random sample of patients enrolled?	No
Did the study avoid inappropriate exclusions?	Yes
Was a 'two‐gate' design avoided?	No
		High	High
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?	Yes
Was a cycle phase considered in interpretation of the result of index test?	No
		High	Low
DOMAIN 3: Reference Standard
Is the reference standards likely to correctly classify the target condition?	Yes
Were the reference standard results interpreted without knowledge of the results of the index tests?	Yes
		Low	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

AA: arachidonic acid; AEA: anti‐endometrial antibodies; AUB: abnormal uterine bleeding; BMI: body mass index; BTL: bilateral tubal ligation; CAD: coronary artery disease; CFU: colony‐forming unit; CRP: C‐reactive protein; CV: coefficient of variation; Da: dalton; DIE: deep infiltrating endometriosis; DTA: decision tree algorithm; DTNB: Ellman's reagent (5.5'‐dithiobis‐(2‐nitrobenzoic acid); ECLIA: electro‐chemiluminescence immunoassay; EIA: enzyme immunoassay; ELISA: enzyme‐linked immunosorbent assay; EPA: eicosapentaenoic acid; ESHRE: European Society of Human Reproduction and Embryology; ESI‐MS/MS: electrospray ionization mass spectrometry FACS: Fluorescence‐activated cell sorting; FSH: follicle‐stimulating hormone; HGF: hepatocyte growth factor; hs‐CRP: high sensitivity C‐reactive protein; IIF: indirect immunofluorescence; IRMA: immunoradiometric assay; IUD: intrauterine device; kd: kilodalton; KIR: killer inhibitory receptor; LH: luteinising hormone; LOOH: lipid hydroperoxides; LPS: lipopolysaccharide; LS‐SVM: least squares support vector machine; MEIA: microparticle enzyme immunoassay; MF: menstrual fluid; miR: microRNA; MPV: mean platelet volume; MRI: magnetic resonance imaging; mRNA: messenger RNA; MW: molecular weight; n: number of events/number in study arm; N: total sample size; NK: natural killer cell; NSAID: nonsteroidal anti‐inflammatory drugs; OCP: oral contraception pill; OD: optical density; O&G: obstetrics and gynaecology; PB: peripheral blood; PBL: peripheral blood lymphocytes; PCaa: phosphatidylcholine; PCae: etherphospholipid; PCOS: polycystic ovary syndrome; PID: pelvic inflammatory disease; PF: peritoneal fluid; PL: plasma; SELDI‐TOF‐MS: surface enhanced laser desorption/ionisation time of flight mass spectrometry; (r)AFS: (revised) American Fertility Society; (r)ASRM: (revised) American Society for Reproductive Medicine; RCOG: Royal College of Obstetricians and Gynaecologists; RIA: radioimmunoassay; RDF: research development fund; RT‐PCR: real time polymerase chain reaction; SD: standard deviation; SMOH: hydroxysphingomyelin; TVUS: transvaginal ultrasound; VAS: visual analogue scale; WBC: white blood cell.

For a comprehensive list of all biomarkers with their biological annotation, please see Appendix 1.