Gilabert‐Estelles 2003.

Study characteristics
Patient sampling	Primary objective: to analyse several components of the plasminogen activator (PA) pathway and the matrix metalloproteinase (MMP) system in endometriotic tissue, endometrium and peritoneal fluid from women with and without endometriosis Participants: women undergoing laparoscopy/laparotomy at the authors' institution for various indications Selection criteria: exclusion criteria: no hormonal treatment for 3/12 months preceding or pregnant/breastfeeding for 6/12 months before surgery Study design: observational two‐gate, prospective sample collection
Patient characteristics and setting	Clinical presentation: endometriosis group ‐ pelvic pain (n = 16) and infertility (n = 23); controls ‐ pelvic pain (n = 4), infertility (n = 3), pelvic floor defect (n = 3), asymptomatic (n = 25) Age: mean age 35 years (range 23‐47), endometriosis; 40 years (range 29‐47), controls Number enrolled: 74 women (19 in proliferative, 51 in secretory and 4 in menstrual cycle phase) Number available for analysis: 56 women Setting: university hospital ‐ Hospital Universitario La Fe Place of study: Valencia, Spain Period of study: not provided Language: English
Index tests	Index test: plasminogen activators: tPA, uPA, uPAR, PAI‐1, PAI‐2, PAI‐3, tPA‐PAI3, uPA‐PAI3 and MMPs: TIMP‐1, MMP‐3 Description of positive case definition by index test as reported: antigen levels of each of the tested markers assessed with a commercially available ELISAs (in cytosolic and membrane extracts); functional levels of tPA, PAI‐1 by chromogenic assay and functional level of uPA by immunosorbent activity assay (in cytosolic extract); laboratory techniques described Examiners: no information provided; unclear if blinded to the result of reference standard Interobserver variability: the intra‐ and interassay variabilities for tPA were 8% and 12%; uPA: 4% and 10%; uPAR: 5% and 7%; PAI‐1: 3% and 7%, PAI‐2: 5% and 8%, PAI‐3: 4‐8% and 6‐9%; tPA‐PAI3, uPA‐PAI3: 5‐9% and 7‐12%, MMP‐3: 5% and 9%, TIMP‐1: 4% and 7%
Target condition and reference standard(s)	Target condition: endometriosis Prevalence of target condition in the sample: n/N = 39/74 (53%): all stage III‐IV; controls 35 Reference standard: laparoscopy, n = 35/ laparotomy, n = 39 Description of positive case definition by reference test as reported: visual inspection with systematic examination of the abdominal cavity and attention for early and atypical lesions; staging according to the rASRM classification Examiners: no information provided
Flow and timing	Time interval between index test and reference standard: not specified, but from the context appears that the samples were obtained at surgery Withdrawals: 18 endometriosis patients were not included because endometrial tissue was not collected
Comparative
Notes	Conclusion: The increase in antigenic levels of uPA and MMP‐3 in endometrium of women with endometriosis might contribute to the invasive potential of endometrial cells. Once the ovarian endometriotic cyst is developed, an increase in PAI‐1 and TIMP‐1 is detected and significant proteolytic activity is no longer observed, which could explain the frequent clinical finding of isolated endometriotic cyst without invasion of the surrounding ovarian tissue Comments: For tPA, uPAfc, PAI‐1, PAI‐2, PAI‐3, tPA‐PAI3, uPA‐PAI3, TIMP‐1 there was no statistically significant difference between the groups; no data available for meta‐analysis (Appendix 7) For uPAag and MMP‐3 there was a statistically significant difference between the groups, but there were insufficient data to construct 2 × 2 tables; not included 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?	No
Was a menstrual cycle phase considered in interpreting the index test	No
		High	Low
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?	Unclear
Did all patients receive the same reference standard?	Yes
Were all patients included in the analysis?	No
		High