Da Silva 2014.

Study characteristics
Patient sampling	Primary objective: to evaluate evaluate the presence of MPO, NAG, TNF‐α and VEGF in peripheral and menstrual blood in women with and without endometriosis Participants: women undergoing laparoscopy for chronic pelvic pain, infertility or tubal sterilisation Selection criteria: inclusion criteria: regular menstrual cycles in the 6 months preceding sample collection, no use of hormonal nor anti‐inflammatory agents in the previous 3 months and surgical confirmation or exclusion of endometriosis in agreement with the ESHRE guidelines Study design: observational two‐gate, prospective sample collection
Patient characteristics and setting	Clinical presentation: endometriosis group ‐ pelvic pain, infertility; controls ‐ infertility or request for sterilisation; none of the women had a significant past medical history Age: median age 36 years, range 31‐48 years Number enrolled: 17 women Number available for analysis: 17 women (all in early proliferative cycle phase, day 1‐4) Setting: university hospital ‐ Hospital das Clýnicas at Universidade Federal de Minas Gerais (HC‐UFMG) Place of study: Belo Horizonte, Brazil Period of study: February 2011 to December 2012 Language: English
Index tests	Index test: NAG, MPO, TNF‐α, VEGF in menstrual fluid Description of positive case definition by index test as reported: NAG and MPO activity (expressed as change in absorbance (OD) at 400 and 450 nm, respectively); TNF‐α and VEGF levels measured by using commercial specific ELISA kits; laboratory technique described; threshold not provided Examiners: no information provided; unclear if blinded to the result of reference standard Interobserver variability: not provided
Target condition and reference standard(s)	Target condition: endometriosis Prevalence of target condition in the sample: unable to estimate as two‐gate design (endometriosis n = 10: stage II 5, stage IV 2, undetermined stage 3; controls 7) Reference standard: laparoscopy Description of positive case definition by reference test as reported: diagnosis according to ESHRE guidelines; staging according to rASRM Examiners: no information provided
Flow and timing	Time interval between index test and reference standard: not specified, from the context ‐ perioperative sample collection Withdrawals: none
Comparative
Notes	Conclusion: These findings point to the existence of an increased local inflammatory activity in women with endometriosis. Comments: For NAG, MPO, TNF‐α and VEGF there was no statistically significant difference between the groups ‐ no data available for meta‐analysis (Appendix 7)
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	Yes
		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?	Yes
		Unclear