From the Guidelines
Blood tests such as CRP, ESR, and WBC can indicate the presence of inflammation, but they cannot pinpoint its exact location. These tests are often used to suggest that inflammation is present somewhere in the body, but they do not provide precise anatomical localization. According to the study by 1, serum CRP, ESR, and WBC were found to be elevated in patients with active Charcot neuro-osteoarthropathy, but the wide range of values reported and the low quality of evidence made it difficult to support their use in diagnosing the condition.
Inflammatory Markers
- C-reactive protein (CRP) is a commonly used marker of inflammation, which can rise in response to inflammation anywhere in the body 1.
- Erythrocyte sedimentation rate (ESR) is another marker that can be elevated in the presence of inflammation.
- White blood cell count (WBC) can also be used to indicate inflammation, as it often increases in response to infection or inflammation.
Organ-Specific Inflammation
- Liver enzymes such as ALT and AST can suggest liver inflammation.
- Troponin can indicate heart inflammation.
- Amylase and lipase can suggest pancreatic inflammation. However, these tests only provide clues about which organ might be affected and do not offer precise localization of the inflammation.
Imaging Studies
To determine the exact location of inflammation, imaging studies such as CT scans, MRIs, ultrasounds, or nuclear medicine scans like PET scans are necessary. These imaging techniques can visualize the affected tissues directly, while blood tests serve primarily as indicators that inflammation exists somewhere in the body and may help narrow down which body system is involved 1.
From the Research
Blood Tests for Inflammation
The following blood tests can indicate the presence of inflammation:
Location of Inflammation
While these tests can indicate the presence of inflammation, they do not specifically indicate the location of inflammation. However, the combination of ESR and CRP results can provide some information about the type of inflammation:
- Elevated ESR and low CRP may indicate chronic inflammation or infection 4
- Elevated CRP and low ESR may indicate acute inflammation or infection 4
- Discordance between ESR and CRP results can occur in certain conditions, such as renal insufficiency, low albumin, or rheumatoid arthritis 3, 4
Limitations of Blood Tests
It is essential to note that these blood tests have limitations:
- ESR and CRP can be affected by various factors, such as age, sex, and underlying medical conditions 2, 3, 4
- Normal ESR and CRP results do not necessarily rule out inflammation, as some patients with active inflammation may have normal biomarker levels 5
- The interpretation of ESR and CRP results should be done in conjunction with clinical evaluation and other diagnostic tests 2, 6