The Role of Blood Tests in the Diagnosis and Monitoring of Endometriosis

The Role of Blood Tests in the Diagnosis and Monitoring of Endometriosis
Endometriosis is a common condition in women, often requiring a laparoscopy for a definitive diagnosis. However, blood tests play a vital adjunctive role in monitoring the disease status, assessing ovarian reserve, and ruling out other medical conditions.
Below is an overview of the most important biomarkers and the necessary conditions for testing.

CA-125 (Cancer Antigen 125)-
This is the most well-known biomarker associated with endometriosis. CA-125 is a protein found on the surface of cells in the reproductive organs and some cancer cells
:Increased Levels
Endometriosis: Levels often rise in moderate to severe stages (Grade 3 and 4) and in the presence of endometriomas (chocolate cysts)
Other Causes: Menstruation, pregnancy, uterine fibroids, Pelvic Inflammatory Disease (PID), and ovarian cancer
Important Note: A normal result does not rule out endometriosis (especially in early or mild stages)
:Decreased Levels
Indicates a positive response to treatment (medical or surgical) and a reduction in inflammation

AMH (Anti-Müllerian Hormone)-
While this test does not diagnose endometriosis directly, it is crucial for assessing ovarian reserve in affected patients
:Decreased Levels
Endometriotic tissue and endometriomas can damage healthy ovarian tissue, leading to a lower ovarian reserve
Additionally, AMH levels may drop following surgery to remove ovarian cysts
:Increased Levels
Typically seen in Polycystic Ovary Syndrome (PCOS) and is not directly correlated with endometriosis severity

HE4 Test and ROMA Index-
These tests are sometimes requested alongside CA-125 to differentiate benign endometriotic cysts from ovarian malignancies
Interpretation: In endometriosis, CA-125 levels are typically elevated, while HE4 levels usually remain normal. If both are elevated, further investigation for malignancy is necessary

Inflammatory Markers (CRP and ESR)-
Since endometriosis is a chronic inflammatory disease, general inflammatory markers may be checked
Increase: May indicate active inflammation associated with the disease (non-specific)
Pre-Test Conditions
:To ensure accuracy and avoid false positives (especially for CA-125), please observe the following guidelines
:Timing of the Test
CA-125: The best time to perform this test is when you are not menstruating. Menstrual bleeding can naturally elevate this marker, leading to a false-positive result
AMH: This test can be performed on any day of the menstrual cycle as levels remain stable
:Fasting
Fasting is generally not mandatory for these specific tests. However, if these tests are part of a general check-up (including lipids or glucose), 8 to 12 hours of fasting is recommended
Drinking water is permitted
:Medications
High-dose Biotin supplements can interfere with certain laboratory assay methods. It is recommended to stop taking them 48 to 72 hours before the test (consult your doctor)
:Physical Activity
Avoid strenuous physical exercise immediately before the blood draw

References
:For further reading and scientific verification, refer to the following studies
:Role of CA-125 in Diagnosis
Nisenblat, V., et al. (2016). "Blood biomarkers for the non-invasive diagnosis of endometriosis." Cochrane Database of Systematic Reviews
(This review highlights that while CA-125 is not perfect, it remains the most widely used biomarker.)
:Endometriosis and AMH Levels
Uncu, G., et al. (2013). "Assessment of ovarian reserve in women with ovarian endometriomas." Human Reproduction
(This study confirms that the presence of endometriomas can decrease AMH levels.)
:Combined Use of HE4 and CA-125
Moore, R. G., et al. (2012). "A novel multiple marker bioassay utilizing HE4 and CA125 for the prediction of ovarian cancer in patients with a pelvic mass." Gynecologic Oncology
(This article discusses the importance of using both markers to differentiate benign conditions like endometriosis from malignancies.)