Kim 2007.

Study characteristics
Patient sampling	Primary objective: to evaluate the replication potential of the endometrium in patients with endometriosis by examining hTERT mRNA expression and telomerase activity. Participants: women undergoing laparotomy or operative laparoscopy at the authors institution Selection criteria: exclusion criteria: postmenopausal women, previous hormone or GnRH agonist users, and patients with adenomyosis or endometrial cancer/hyperplasia/polyps Study design: observational, unclear if single‐ or two‐gate, prospective sample collection
Patient characteristics and setting	Clinical presentation: not specified Age: mean age 32.7 ± 6.8 years, endometriosis; 34.6 ± 6.7 years, controls Number enrolled: 60 women Number available for analysis: 60 women (26 in proliferative and 34 in secretory cycle phase) Setting: University hospital ‐ Yongdong Severance Hospital, Yonsei University College of Medicine Place of study: Seoul, South Korea Period of study: September 2005 to March 2006 Language: English
Index tests	Index test: hTERT mRNA, telomerase activity Description of positive case definition by index test as reported: hTERT mRNA expression level as measured by RT–PCR (TaqMan methodology, normalised to the endogenous control GAPDH and compared to the calibrator as per 2‐ΔΔCt method); telomerase ‐ relative telomerase activity (RTA), defined as the activity equivalent to that in 100 molecules of TSR (determined by the telomerase repeat amplification protocol assay, referenced to primary source (Kim et al.,1994); laboratory techniques described; no thresholds provided Examiners: no information provided Interobserver variability: no information provided
Target condition and reference standard(s)	Target condition: endometriosis Prevalence of target condition in the sample: n/N = 30/60 (50%): stage I‐II 8, stage III‐IV 22; controls 30 Reference standard: laparoscopy/laparotomy Description of positive case definition by reference test as reported: disease stages established by rASRM Examiners: no information provided
Flow and timing	Time interval between index test and reference standard: biopsies were performed at surgery Withdrawals: none reported
Comparative
Notes	Conclusion: The demonstrated overexpression of hTERT mRNA and telomerase activity in the endometrium of endometriosis patients suggests that replication potential of endometrial cells may have an important role in the pathogenesis of endometriosis. Comments: For hTERT there was a statistically significant difference between the groups, but there were insufficient data to construct 2 × 2 tables; not included in this review For telomerase activity 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?	Unclear
		High	Unclear
DOMAIN 2: Index Test All tests
Were the index test results interpreted without knowledge of the results of the reference standard?	No
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?	Yes
Did all patients receive the same reference standard?	Yes
Were all patients included in the analysis?	Yes
		Low