Lanzone 1991.

Study characteristics
Patient sampling	Primary objective: to evaluate CA‐125 in serum and peritoneal fluid of women with various stages of endometriosis and in the control subjects Participants: women undergoing laparoscopy for infertility or pelvic pain during luteal phase of the cycle Selection criteria: exclusion criteria: peritoneal fluid positive for mycoplasma and chlamydia Study design: longitudinal single‐gate, prospective recruitment and collection of samples, consecutive series
Patient characteristics and setting	Clinical presentation: pelvic pain, infertility or both Age: mean age 30 ± 6.5 years, range 19‐44 years (endometriosis group), 30 ± 6.9 years, range 19‐41 years (controls) Number of participants enrolled: 270 participants Number of participants available for analysis: 119 participants (all in luteal cycle phase) Setting: Department of O&G, Universita Catolica del Sacro Cuore Place of study: Rome, Italy Period of study: January 1987 ‐ December 1988 Language: English
Index tests	Index test: CA‐125 Details of the index test procedure as stated: serum CA‐125 levels measured with radioimmunoassay (CIS Diagnostici); all samples from the same patient were assayed at the same time Threshold for positive result: CA‐125 > 35.0 U/ml ‐ pre‐specified Examiners: not stated Interobserver variability: the inter‐ and intra‐assay CV were 8% and 15%
Target condition and reference standard(s)	Target condition: endometriosis Prevalence of target condition in the sample: n = 81/270 (30%): stage I‐II 31, stage III‐IV 50; controls n = 38 Reference standard: laparoscopy N = 270 (100%) Description of positive case definition by reference standard test as reported: visual inspection; staging according to the rAFS classification Examiners: not stated
Flow and timing	Time interval between index test and reference standard: blood samples were collected immediately before surgery Withdrawals: 151 participants were excluded (reason not explained)
Comparative
Key conclusions by the authors	The measurement of serum CA‐125 does not appear to be useful for the diagnosis and management of endometriosis.Therefore, at present, laparoscopy should be considered the most specific and sensitive method of detecting and following the disease
Conflict of interest	Not reported
Notes	The reported estimates for peritoneal fluid and the estimates following medical treatment for endometriosis are not presented in this review The reported diagnostic estimates per stages of severity of endometriosis are not presented 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?	Yes
Did the study avoid inappropriate exclusions?	Yes
Was a 'two‐gate' design avoided?	Yes
		Unclear	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?	Yes
Was a cycle phase considered in interpretation of the result of index test?	Yes
		Unclear	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?	No
		High