At-Home Inflammation Tests: What CRP, hs-CRP, and ESR Results Mean

What Inflammation Markers Show

Inflammation is your immune system’s response to injury, infection, and many other conditions. Short-term inflammation helps the body heal. Ongoing inflammation can be a sign of a chronic health condition.

Inflammation markers are blood tests that rise when inflammation is present. According to MedlinePlus, they’re nonspecific: they can show that inflammation is happening somewhere in the body, but they can’t pinpoint the location or the reason.

C-Reactive Protein (CRP)

CRP is a protein made by the liver. Its level rises when there’s inflammation in the body and falls as inflammation settles.

According to MedlinePlus, healthy people generally have very low amounts of CRP in their blood. A value of about 0.8 to 1.0 mg/dL or lower is thought to be healthy, and increases above normal may mean inflammation is present.

Providers use CRP to check for flare-ups of inflammatory conditions and to see whether treatment for inflammation is working. A falling CRP can be a sign of improvement.

High-Sensitivity CRP (hs-CRP)

An hs-CRP test measures the same protein but can detect much smaller increases. It’s mainly used to help estimate the risk of heart disease. Many at-home inflammation tests report hs-CRP, so check which one your kit uses.

The American Heart Association (AHA) and CDC group hs-CRP results like this:

These categories describe heart disease risk, not inflammation from a specific illness. The AHA and CDC recommend averaging two hs-CRP measurements taken about two weeks apart. If a result is above 10 mg/L, it may reflect an infection or another acute source of inflammation, and testing should be repeated after that has been looked into.

The AHA/CDC writing group also said there’s no need for hs-CRP screening of the entire adult population. For most people, the focus should stay on major risk factors such as blood pressure, cholesterol, smoking, and diabetes.

Erythrocyte Sedimentation Rate (ESR)

ESR, or “sed rate,” measures how quickly red blood cells settle to the bottom of a tall, thin tube. Inflammation makes red blood cells clump together, so they sink faster. A faster rate suggests more inflammation.

Normal ESR ranges vary with age and sex. MedlinePlus notes that pregnancy, the menstrual cycle, aging, obesity, regular alcohol use, exercise, and some medicines and supplements can also affect results. It’s also possible to have an inflammatory condition and still have a normal ESR.

ESR is often ordered alongside CRP to give a fuller picture. If you’re considering a home test, check whether ESR is included, since many kits focus on CRP.

CRP vs. hs-CRP vs. ESR

Watch the units. Standard CRP is often reported in mg/dL, while hs-CRP is usually reported in mg/L. Since 1 mg/dL equals 10 mg/L, it’s easy to misread a result if you mix them up.

What These Tests Can’t Tell You

• The cause. Infections, injuries, autoimmune conditions, inflammatory bowel disease, heart disease, and some cancers can all raise inflammation markers.
• The location. A high result doesn’t show where inflammation is happening.
• A diagnosis on its own. MedlinePlus notes that providers interpret these markers alongside other tests, symptoms, and medical history.
• That nothing is wrong. A normal result doesn’t rule out every inflammatory condition.

Inflammation Tests and Lyme Disease

Because CRP and ESR are nonspecific, they can’t diagnose Lyme disease or show whether a Lyme infection is still present. Lyme disease is diagnosed based on symptoms, likely tick exposure, and, when appropriate, FDA-cleared antibody testing. Learn more in our guide to Lyme disease tests.

That said, if you have ongoing symptoms like joint pain or fatigue, inflammation markers can be one helpful piece of information for your provider, especially when looking for other conditions that could be contributing. Our inflammation symptoms guide explains more about inflammation and Lyme disease.

Tips for Accurate Results

• Test when you’re well. A recent infection or injury can raise inflammation markers, and exercise can affect ESR. The AHA and CDC advise against hs-CRP testing for heart risk until at least two weeks after an acute illness has resolved.
• Tell your provider about medicines and supplements. Some can affect results, according to MedlinePlus.
• Follow the kit instructions exactly, including how to collect and ship your sample.
• Repeat before drawing conclusions. One result is a snapshot. Compare repeat tests from the same lab and method.

For help choosing a test company, see our checklist in How At-Home Lab Tests Work.

What to Do With Your Results

1. Share them with your provider, including the units and reference range.
2. Seek prompt care for high results with symptoms. A high CRP with fever or feeling very unwell needs medical attention.
3. Look at the bigger picture. Your provider may suggest repeat testing or other tests to find the cause.
4. Focus on what you can change. Sleep, activity, diet, and managing other health conditions all matter for overall health.

Curious about supplements often discussed for inflammation? Our supplement guides explain what the research does and doesn’t show, including safety and interactions.

Frequently Asked Questions

What is a normal CRP level?

MedlinePlus says healthy people have very low CRP, with about 0.8 to 1.0 mg/dL or lower thought to be healthy. Ranges vary by lab, so use the reference range on your report.

Are at-home inflammation tests accurate?

Accuracy depends on the lab, the test method, and careful sample collection. Choose a company that uses a certified laboratory, and repeat a surprising result before acting on it.

Is hs-CRP the same as CRP?

They measure the same protein, but hs-CRP detects much smaller amounts and is mainly used to help estimate heart disease risk.

Can a recent illness affect my results?

Yes. Infections and injuries can raise inflammation markers. For heart risk testing, the AHA and CDC suggest waiting until you’ve recovered and repeating a high hs-CRP result about two weeks later.

Can a CRP test show if I still have Lyme disease?

No. CRP can show inflammation, but it can’t identify the cause or show whether a Lyme infection is present.

The Takeaway

At-home inflammation tests usually measure CRP or hs-CRP, which can show that inflammation is present but not what’s causing it.

Standard CRP looks for higher levels of inflammation, hs-CRP helps estimate heart disease risk, and ESR is another general marker often used alongside CRP. Test when you’re well, check the units, and repeat unexpected results.

Share your results with your provider, who can interpret them alongside your symptoms and history.