Where CRP is reported
Also listed as: Acute phase protein; C-Reactive Protein (CRP)
| Condition | Direction | Compared against | Associated symptoms | Source |
|---|---|---|---|---|
| Atrial Fibrillation | ↑ elevated | AF vs normal population | — | Jabati et al. 2018 |
| COPD | ↑ elevated | smokers/COPD vs non-smokers | — | Yanbaeva et al. 2007 |
| Gulf War Illness | ↑ elevated | healthy Gulf War veteran controls | Chronic low-grade inflammation | Johnson et al. 2016 |
| Inflammatory Bowel Disease (Crohn's/UC) | ↑ elevated | active/moderate-to-severe IBD vs symptomatic remission | — | Singh et al. 2023 |
| Long COVID | ↑ elevated | healthy controls, recovered individuals without persistent symptoms | General inflammation marker | Lai et al. 2023 |
| Low Back Pain | ↑ elevated | nonspecific LBP vs healthy (association evidence) | — | Lim et al. 2020 |
| Lyme Disease | ↕ inconsistent | healthy controls | Variable in Lyme — often normal | Lantos et al. 2021 |
| Major Depressive Disorder | ↑ elevated | females with depression vs healthy female controls | — | Jarkas et al. 2024 |
| ME/CFS | ↕ inconsistent | healthy controls | Low-grade inflammation | Strawbridge et al. 2019 |
| Osteoarthritis | ↑ elevated | OA vs healthy (elevated but less than RA) | — | Sipe et al. 1995 |
| Rheumatoid Arthritis | ↑ elevated | RA vs healthy (acute phase reactant, classification criterion) | — | Kourilovitch et al. 2014 |
Frequently asked questions
In which conditions is CRP altered?
In the OSMF atlas CRP is reported in Atrial Fibrillation, COPD, Gulf War Illness, Inflammatory Bowel Disease (Crohn's/UC), Long COVID, Low Back Pain, Lyme Disease, ME/CFS, Major Depressive Disorder, Osteoarthritis, Rheumatoid Arthritis. It is elevated in 9, mixed in 2 across 11 entries.
Does CRP point to one specific diagnosis?
No. Because CRP changes in several conditions (Atrial Fibrillation, COPD, Gulf War Illness, Inflammatory Bowel Disease (Crohn's/UC), Long COVID, Low Back Pain, Lyme Disease, ME/CFS, Major Depressive Disorder, Osteoarthritis, Rheumatoid Arthritis), an abnormal result cannot identify which condition, if any, is present. It must be interpreted with symptoms, history and other tests.
What is the LOINC code for CRP?
Entries in this atlas use LOINC 1988-5. LOINC codes identify the laboratory observation so results can be compared across systems.
Is one abnormal CRP result diagnostic?
No single biomarker result is diagnostic of any of these conditions. Findings reflect group averages from published cohorts with substantial overlap between patients and controls.
Cite this page
Subscribe on Substack
Last reviewed: 2026-07-03 · Browse: Biomarker Index · All marker pages · Biomarker Atlas
Disclaimer: Educational synthesis of peer-reviewed research; not medical advice. Findings are group-level and vary with study design. Discuss any result with a qualified clinician.