Table 1 Characteristics of the included studies

de Arellano

Germany

2013

Peritoneal endometriotic lesions

NA

Peritoneal fluid

NA

40 (20/20)

Fair

Bucci

Italy

2011

NA

Stages 1 and 2

Plasma

case = 28.36 ± 3.9

control = 26.81 ± 4.53

22 (11/11)

Fair

Browne

USA

2012

NA

NA

Eutopic endometrial biopsy

case = 34 ± 7

control = 34 ± 6

33 (18/15)

Good

Herranz-Blanco

Spain

2023

superficial peritoneal lesions = 54 (39.7%)

ovarian endometriomas = 26 (19.1%)

deep infiltrating endometriosis = 29 (21.3%)

deep infiltrating endometriosis and ovarian endometriomas = 25 (18.4%)

Unclassified = 2 (1.5%)

rASRM classification

I–II = 68 (50%)

III–IV = 68 (50%)

serum samples

case = 35.6 ± 6.42

control = 33.5 ± 5.96

204 (136/68)

Fair

Giannini

Italy

2010

NA

stage I and II

plasma and follicular fluid

case = 29.8 ± 4.13

control = 27.7 ± 4.7

56 (26/30)

Poor

Dwiningsih

Indonesia

2022

Ovarian endometriosis n = 32 (88.9)

Peritoneal endometriosis n = 4 (11.1)

rASRM classification

I = 3 (8.3)

II = 1 (2.8)

III = 11 (30.6)

IV = 21 (58.3)

Serum

case = 31.47 ± 6.5

control = 38.14 ± 4.4

50 (36/14)

Good

Ding

People’s Republic of China

2017

Ovarian endometrioma

Revised American Fertility Society

scoring system

I–II = 32 (53.3%)

III–IV = 28 (46.7%)

Serum and peritoneal fluid

case = 35.3 ± 0.9

control = 35.6 ± 1.4

98 (60/38)

Good

Yu

USA

2023

NA

NA

Peritoneal fluid

Cases = 38.0 ± 6.0

Control = 43.0 ± 4.5

40 (14/26)

Good

Wessels

Canada

2016

NA

I: 10

II: 9

III: 10

IV: 64

Plasma

Cases = 34.7 ± 7.0

Control = 29.9 ± 8.5

104 (68/36)

Fair

Stefani

Brazil

2019

NA

NA

serum

NA

53 (36/17)

Fair

Perricos

Austria

2018

22 superficial peritoneal

3 deep infiltrating

12 endometrioma

32 combination of two

7 combination of three

I:21

II: 14

III: 20

IV: 20

serum

Cases = 33.7 ± 6.04

Controls = 34.8 ± 6.9

128 (77/51)

Good

Liang

China

2020

NA

NA

serum

NA

157 (82/75)

Poor