Artwork by Kathleen Sluka

For most people, pain goes away when an injury heals. But for some people, pain after surgery can linger, and can last for years or even a lifetime. The Acute to Chronic Pain Signatures (A2CPS) project is a bold research initiative - the largest and most comprehensive of its kind - being carried out by a nation-wide consortium of researchers. The findings will help researchers to develop better, more individualized treatments for patients and to better understand the complex biological processes underlying chronic pain.

About A2CPS


A2CPS will collect questionnaires, blood samples and brain imaging from 2,800 participants before and for up to 12 months after having total knee replacement or thoracic surgery.


Many diseases can be diagnosed, tracked and predicted with biological markers, or biomarkers, but none are yet known for chronic pain. The major aim of A2CPS is to find biomarkers or bio-signatures of the transition to chronic pain.


The A2CPS consortium is organized into four main hubs, with over 100 investigators and staff around the country. Our researchers span a wide range of expertise, from basic scientists to clinicians to data management experts.


In addition to biological specimens, A2CPS also collects different types of data from our participants, including patient-reported outcomes (PROs) and quantitative sensory testing (QST), among others.

Omics from Blood

The term “omics” refers to the collection of information about the molecules found in our blood, which can tell us about the activity of genes, proteins, lipids and metabolites in our cells and tissues.

Brain Imaging

Previous studies have identified “signatures” of brain activity that reflect a painful experience, and others that predicted who was more likely to develop chronic pain. A2CPS will include brain-imaging data in our search for biosignatures of chronic pain.

Latest News

NIH Funding Opportunity

Published Apr 2024

The NIH Common Fund is offering new R03 funding to encourage use of existing Common Fund datasets, including A2CPS. To be eligible, the proposed research must substantially leverage data from at least two Common Fund programs. See a full list of programs here, and apply by June 27, 2024.

NIH Pain Consortium Symposium

Published Mar 2024

The NIH Pain Consortium holds their annal symposium May 30 - 31, 2024, at Natcher Auditorium at the NIH in Bethesda, MD. The theme this year is Sex and Gender Differences in the Neurobiology of Pain, its Experience and Management.​​​