Blood Tests for Inflammation: Key Components and Levels

What Are Blood Tests for Inflammation?

Blood tests for inflammation measure specific markers that show if there is inflammation in your body. Inflammation is your body’s natural response to injury or infection, but sometimes it can happen without a clear reason, like in autoimmune diseases.

Doctors use these tests to check for inflammation that might be related to conditions like infections, chronic illnesses, or injuries. The tests measure markers such as C-reactive protein (CRP) or erythrocyte sedimentation rate (ESR). High levels of these markers mean there is inflammation in the body.

These tests do not diagnose a disease, but they help doctors understand if more tests are needed to find the cause of inflammation. If the results show high inflammation, your doctor may suggest further testing to identify the underlying issue.

When Are These Tests Recommended?

Blood tests for inflammation are recommended in several situations. Doctors often use them to diagnose or monitor conditions related to inflammation. Here are common reasons why these tests are ordered:

• Unexplained symptoms: If you have joint pain, swelling, fatigue, or unexplained fevers, doctors may suspect inflammation is the cause and order these tests to confirm it.
• Autoimmune conditions: Tests for inflammation are often used to diagnose autoimmune diseases like rheumatoid arthritis or lupus, where long-term inflammation is common.
• Infections: These tests can help identify infections by detecting elevated levels of inflammation markers in your blood.
• Monitoring treatment progress: During treatment for inflammatory conditions, these tests check if inflammation is going down and if the treatment is working.
• Post-surgery or injury: After surgery or trauma, inflammation tests may be ordered to check for any complications, such as infection or ongoing inflammation.

In summary, these tests are important for diagnosing and managing a range of conditions where inflammation is a key factor.

Inflammatory Markers

Several blood tests can detect inflammation in the body. Each test looks for different markers that show whether inflammation is present and how severe it may be. Here are the most common blood tests used for this purpose:

C-Reactive Protein (CRP) Test

The CRP test measures the amount of C-reactive protein in your blood. CRP is a protein produced by the liver in response to inflammation. 

When levels are elevated, it often indicates acute or chronic inflammation in the body. Doctors use this test to detect infections, autoimmune diseases like lupus, and inflammatory conditions such as rheumatoid arthritis. 

It is also helpful in monitoring inflammation during treatment.

CRP can be measured through a standard blood test, which gives general information about inflammation. 

Another version, the high-sensitivity CRP (hs-CRP) test, is used to evaluate low levels of inflammation. This version is often used in heart disease risk assessments, as even mild inflammation can increase cardiovascular risks.

Procalcitonin Test

The procalcitonin test measures the level of procalcitonin, a substance that increases significantly in response to bacterial infections. This test is especially useful for detecting serious bacterial infections and sepsis. 

High levels of procalcitonin in the blood indicate the presence of a bacterial infection, making it a valuable marker for determining if antibiotic treatment is necessary.

Procalcitonin levels can also help differentiate between bacterial and viral infections, as viral infections typically don’t cause significant increases in this marker.

Procalcitonin is measured through a standard blood test and is most often used in hospitals or emergency settings when a serious infection is suspected.

Erythrocyte Sedimentation Rate (ESR)

The ESR test measures how quickly red blood cells fall to the bottom of a test tube. Normally, red blood cells settle slowly. However, when there is inflammation in the body, they settle more quickly. While ESR does not pinpoint where the inflammation is, it helps show the presence and extent of inflammation.

This test is often used alongside other blood tests to help diagnose conditions like autoimmune diseases, infections, and cancers. It’s also used to monitor conditions like polymyalgia rheumatica and temporal arteritis.

Fibrinogen Test

Fibrinogen is a protein that helps in blood clotting, but its levels increase when there is inflammation. A fibrinogen test measures the concentration of this protein in the blood, helping to detect inflammation and clotting issues. 

Elevated fibrinogen levels can indicate conditions like heart disease, chronic inflammation, or tissue damage.

The fibrinogen test is typically part of a panel of blood tests that assess your clotting function, like the coagulation panel, or inflammation levels in the body. Doctors may order this test if you have unexplained inflammation or blood clotting disorders.

Plasma Viscosity Test

Plasma viscosity measures how thick your blood is. When the body is inflamed, the proteins that cause inflammation can make the blood thicker, which increases the plasma viscosity. 

This test helps detect systemic inflammation and is sometimes used to monitor conditions like vasculitis, multiple myeloma, or chronic inflammatory diseases.

The plasma viscosity test is less commonly ordered but may be used when doctors suspect chronic or systemic inflammation. 

It is often used in combination with other tests, such as CRP or ESR, to provide a fuller picture of inflammatory activity in the body.

How to Prepare for a Inflammation Blood Tests

Most blood tests for inflammation don’t need special preparation. However, follow your doctor’s instructions for the best results.

Sometimes, your doctor may ask you to fast for 8-12 hours, especially if the test is part of a broader panel. Let your doctor know if you’re taking any medications, as some can affect the results.

On the test day, wear clothing that makes it easy to access your arm, and stay hydrated to help with the blood draw.

How to Interpret Blood Test Results for Inflammation

Interpreting blood test results for inflammation helps doctors understand if your body is experiencing inflammation and how severe it is. Different tests measure different markers, and your results will show whether these markers are within normal ranges.

Note: The units of measurement and the normal ranges can differ depending on the laboratory and the specific methods used.

If the results show normal levels, it usually means there is no significant inflammation in your body. 

When results show high levels of markers, it indicates inflammation. High levels may suggest infections, autoimmune diseases, or other chronic inflammatory conditions. 

Your doctor will analyze the results to determine the cause and may order additional tests to confirm the diagnosis.

In some cases, inflammation markers can be mildly elevated due to temporary factors like an infection or injury. If this happens, your doctor might recommend a follow-up test to see if levels return to normal.

Possible Follow-Up Tests

If your blood test results show high levels of inflammation markers, your doctor may recommend follow-up tests to pinpoint the cause. These additional tests help identify the underlying condition and guide appropriate treatment.

• Complete Blood Count (CBC): A CBC checks your overall health and detects a variety of disorders, such as infections, anemia, or blood diseases, which can be linked to inflammation.
• Autoimmune Panels: If autoimmune diseases are suspected, tests like the antinuclear antibody (ANA) test can be used to check for conditions such as lupus, rheumatoid arthritis, or Sjögren’s syndrome.
• Infection-Specific Tests: If an infection is suspected, your doctor may order tests like blood cultures to identify bacterial infections or viral load tests for viral infections.
• Imaging Tests: In some cases, imaging tests like X-rays, CT scans, or MRIs may be needed to look for inflammation or damage in tissues or organs. This is common when joint or organ inflammation is suspected.
• Liver or Kidney Function Tests: Chronic inflammation can sometimes affect your liver or kidneys. These tests assess how well these organs are functioning and whether inflammation is impacting them.