Mihalyi 2010.

Study characteristics
Patient sampling	Primary objective: to evaluate the combined performance of 6 potential plasma biomarkers in the diagnosis of endometriosis Participants: women who underwent laparoscopy for subfertility with or without pain at the authors' institution ‐ identified through electronic database of the bio bank samples Selection criteria: exclusion criteria: samples collected from women who were on hormonal medication or had other pelvic inflammatory disease or general diseases at the time of collection, surgery within 6 months prior to the time of collection Study design: cross‐sectional single‐gate, prospective collection of samples, retrospective selection of cases
Patient characteristics and setting	Clinical presentation: pelvic pain, infertility or both Age: reproductive age Number of participants enrolled: 294 women Number of participants available for analysis: 294 women (59 in menstrual, 119 in follicular, 116 in luteal cycle phase) Setting: Department of O&G, University Hospital Gasthuisberg Place of study: Leuven, Belgium Period of study: not specified; samples collected since 1999 Language: English
Index tests	Index test: IL‐6, IL‐8, TNF‐α, hsCRP, CA‐125, CA‐19.9 Details of the index test procedure as stated: plasma concentrations of IL‐6, IL‐8 and TNF‐α were determined by using commercially available ELISA kits (BD Biosciences, Erembodegem,Belgium) according to the manufacturer's instructions. Plasma concentrations of CA‐125, CA‐19.9 and hsCRP levels were measured by automated assays on a Roche Modular P or Modular E170 instruments (Roche, Vilvoorde, Belgium) at the central laboratories of the university Hospitals Leuven (Gasthuisberg, Leuven). The predictive model was built by using a multivariate analysis (stepwise logistic regression with and without LSSVM analysis Threshold for positive result: not provided Examiners: no information provided; unclear if were 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: n = 201/294 (68%): stage I‐II 132, stage III‐IV 69; controls n = 93 Reference standard: laparoscopy n = 294 (100%) + histopathology Description of positive case definition by reference standard test as reported: visual inspection with histological confirmation for most of the samples; rASRM classification Examiners: no information provided
Flow and timing	Time interval between index test and reference standard: blood samples collected before anaesthesia Withdrawals: none
Comparative
Key conclusions by the authors	Advanced statistical analysis of a panel of 6 selected plasma biomarkers on samples obtained during the secretory phase or during menstruation allows the diagnosis of both minimal–mild and moderate–severe endometriosis with high sensitivity and clinically acceptable specificity
Conflict of interest	Not reported; supported by a TBM (Toegepast Biomedisch Onderzoek met Primair Maatschappelijke Finaliteit) grant from the Institute for Innovative Science and Technology IWT (Innovatie door Wetenschap en technologie) in Flanders, Belgium
Notes	The reported diagnostic estimates according to severity of endometriosis are not presented in this review The diagnostic estimates for each individual marker were reported only for luteal cycle phase and were the result of univariate logistic regression model The diagnostic estimates for the combination of biomarkers were reported for the overall group and for each cycle phase and were the results of multivariate logistic regression and LS‐SVM models
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 cycle phase considered in interpretation of the result of index test?	Yes
		High	Low
DOMAIN 3: Reference Standard
Is the reference standards likely to correctly classify the target condition?	Yes
Were the reference standard results interpreted without knowledge of the results of the index tests?	Yes
		Low	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