Lee 2010.

Study characteristics
Patient sampling	Primary objective: to study the expression of vascular endothelial growth factor (VEGF), endocrine gland‐derived VEGF (EG‐VEGF/PK1), and its receptors (PKR1 and PKR2) in eutopic and ectopic endometrial tissues Participants: infertile women undergoing diagnostic laparoscopy for tubal patency Selection criteria: inclusion criteria: regular cycles, no inflammatory or hormonal medication for at least 3/12 months before surgery Study design: observational single‐gate, prospective sample collection
Patient characteristics and setting	Clinical presentation: infertility Age: mean age 34 years (range 29–38), endometriosis; 33 years (range 24–39), controls Number enrolled: 48 women Number available for analysis:48 women (23 in proliferative and 25 in secretory phase of the cycle) Setting: University reproduction unit, LKS Faculty of Medicine, the University of Hong Kong Place of study: Hong Kong, China Period of study: not stated Language: English
Index tests	Index test: EG‐VEGF, PKR 1 and PKR2 mRNA Description of positive case definition by index test as reported: mRNA levels detected by RTPCR following laser‐captured microdissection (detection by ABI 7500 Sequence Detector (Applied Biosystems, CA); relative gene expression values were calculated by the 2‐ΔΔCt method, normalised to endogenous control 18S); laboratory technique described; no threshold provided Examiners: none stated; unclear if were blinded to the results of reference standard Interobserver variability: not provided
Target condition and reference standard(s)	Target condition: endometriosis Prevalence of target condition in the sample: n/N = 15/48 (31%); stages not specified; controls 33 Reference standard: laparoscopy Description of positive case definition by reference test as reported: rAFS scoring was used to classify the stages of endometriosis Examiners: none stated
Flow and timing	Time interval between index test and reference standard: not specified, but from context appears that tissue were collected at surgery Withdrawals: none reported
Comparative
Notes	Conclusion: Expression of VEGF mRNA and protein was higher in red peritoneal endometriotic lesion than in other types of peritoneal lesions. There was no difference in the mRNA expression of VEGF between eutopic endometrium and ovarian endometriotic tissues. Comment: For EG‐VEGF, PKR 1 and PKR2 mRNA 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?	Yes
		High	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 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