Peritoneal aspiration (drainage of fluid from the abdomen)

Peritoneal aspiration is a diagnostic test that takes a sample of fluid from the peritoneum to see if it contains cancer cells.

What is the peritoneum?

The organs in the tummy (abdomen) are covered by a lining (membrane) called the peritoneum. It has an inner and outer layer. The inner layer covers the organs in the abdomen. The outer layer lines the abdominal wall.

The peritoneum helps protect the organs in the abdomen and keeps them in place. When mesothelioma develops in the peritoneum, it causes the layers of the peritoneum to thicken.


Side view of the tummy (abdomen) showing the peritoneum
Image: Side view of the tummy (abdomen) showing the peritoneum


What is peritoneal aspiration?

Mesothelioma cells can cause fluid to collect in the abdomen. This is called ascites. Your doctor may take a sample of this fluid to send to the laboratory, to see if it contains mesothelioma cells. This is called a peritoneal aspiration.

You may have an ultrasound scan during the test. Ultrasound uses sound waves to build up a picture of the area. This helps guide the doctor to where the fluid is. Your doctor will give you a local anaesthetic to numb the area first. After this, they pass a needle through your skin into the fluid to take a sample.

About our information

  • References

    Below is a sample of the sources used in our mesothelioma information. If you would like more information about the sources we use, please contact us at

    Woolhouse I et al. British Thoracic Society Guideline for the investigation and management of malignant pleural mesothelioma. Thorax. 2018.

    Thomas A et al. Mesothelioma. BMJ Best Practice. 2019.

    Baas P et al. Malignant pleural mesothelioma: ESMO Clinical Practice Guidelines for diagnosis, treatment and follow-up.  Annals of Oncology. 26 (Supplement 5): v31–v39. 2015. Available from:

    Kusamara S et al. Peritoneal mesothelioma: PSOGI/EURACAN clinical practice guidelines for diagnosis, treatment and follow-up. European Journal of Surgical Oncology. March 2020.

  • Reviewers

    This information has been written, revised and edited by Macmillan Cancer Support’s Cancer Information Development team. It has been reviewed by expert medical and health professionals and people living with cancer. It has been approved by Senior Medical Editor, Dr David Gilligan, Consultant Clinical Oncologist.

    Our cancer information has been awarded the PIF TICK. Created by the Patient Information Forum, this quality mark shows we meet PIF’s 10 criteria for trustworthy health information.

Date reviewed

Reviewed: 01 August 2021
Next review: 01 August 2024
Trusted Information Creator - Patient Information Forum
Trusted Information Creator - Patient Information Forum

Our cancer information meets the PIF TICK quality mark.

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