Question: Is there is any evidence to suggest biopsy of laparoscopically diagnosed endometriosis can be negative?
Please note: the search for this response was carried out over 1 year ago. Eligible users may request an update of the evidence by submitting a new Clinical Query here.
Answer: The RCOG green-top guideline on the investigation and management of endometriosis (1) notes that “Laparoscopy is the gold standard diagnostic test in clinical practice. A meta-analysis of its value against a histological diagnosis showed (assuming a 10% pre-test probability of endometriosis) that a positive laparoscopic examination increases the likelihood of detecting the disease to 32% (95% CI 21–46%) and a negative laparoscopy decreases the likelihood to 0.7% (95% CI 0.1–5.0%).” This is based on a systematic review of the accuracy of laparoscopy in the diagnosis of endometriosis (2)
(Evidence level 1a)
The guideline also makes the following good practice point: “Positive histology confirms the diagnosis of endometriosis; negative histology does not exclude it.”
(Evidence level IV)
Negative biopsy in laparoscopically-diagnosed endometriosis has also been reported in more recent trials (3-4)
- The Investigation and Management of Endometriosis (Green-top 24) RCOG 2006
- Wykes CB. Clark TJ. Khan KS. Accuracy of laparoscopy in the diagnosis of endometriosis: a systematic quantitative review. BJOG: An International Journal of Obstetrics & Gynaecology. 111(11):1204-12, 2004 Nov. Full text available to Fellows, Members and Trainees.
- de Almeida Filho DP. de Oliveira LJ. do Amaral VF. Accuracy of laparoscopy for assessing patients with endometriosis. Sao Paulo Medical Journal = Revista Paulista de Medicina. 126(6):305-8, 2008 Nov. Full text
- El Bishry G. Tselos V. Pathi A. Correlation between laparoscopic and histological diagnosis in patients with endometriosis. Journal of Obstetrics & Gynaecology. 28(5):511-5, 2008 Jul. Abstract
Search date: April 2009
Classification of evidence levels
Ia Evidence obtained from meta-analysis of randomised controlled trials.
Ib Evidence obtained from at least one randomised controlled trial.
IIa Evidence obtained from at least one well-designed controlled study without randomisation.
IIb Evidence obtained from at least one other type of well-designed quasi-experimental study.
III Evidence obtained from well-designed non-experimental descriptive studies, such as comparative studies, correlation studies and case studies.
IV Evidence obtained from expert committee reports or opinions and/or clinical experience of respected authorities.
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