Type

Blood

Part of

Metabolic syndrome

Part of

Metabolic syndrome

Blood biomarker

Part of

Metabolic syndrome

High Sensitivity C-Reactive Protein (hsCRP)

High sensitivity CRP (C-reactive protein) is a sensitive marker of inflammation in the body.

High Sensitivity C-Reactive Protein (hsCRP)

Normal range

<5 mg/L

Normal range

<5 mg/L

Normal range

High Sensitivity C-Reactive Protein (hsCRP)

High sensitivity CRP (C-reactive protein) is a sensitive marker of inflammation in the body.

High Sensitivity C-Reactive Protein (hsCRP)

Normal range

<5 mg/L

Normal range

<5 mg/L

Normal range

High Sensitivity C-Reactive Protein (hsCRP)

High sensitivity CRP (C-reactive protein) is a sensitive marker of inflammation in the body.

High Sensitivity C-Reactive Protein (hsCRP)

Normal range

<5 mg/L

Normal range

<5 mg/L

Normal range

High Sensitivity C-Reactive Protein (hsCRP)

Dr. Yiannis Balanos

MBBS MRCGP

The Inflammation Detector

C-Reactive Protein (CRP) is your body's alarm system for inflammation - a protein that rises rapidly when your immune system detects threats like infections, injuries, or chronic diseases. This sensitive marker can help doctors identify and monitor inflammatory conditions throughout your body, from acute infections to chronic diseases like heart disease and arthritis.

CRP is a substance produced by the liver in response to inflammation. Its level in your bloodstream can rise dramatically when your body is fighting something off. While it doesn't pinpoint the exact location or cause of the problem, a CRP test provides a crucial clue that your immune system is hard at work.

Get tested

What Triggers Your CRP to Rise

Discover the infections, injuries, and chronic diseases that cause this inflammation marker to spike in your blood.

When High CRP Signals Problems

Learn about the conditions that cause CRP elevations requiring medical attention.

Understanding CRP vs. High-Sensitivity CRP

Find out the difference between standard CRP testing and the more sensitive version used for heart disease risk assessment.

Understanding Your Results

Understand how to interpret CRP levels and what additional tests might be needed for diagnosis.

What Triggers Your CRP to Rise

CRP levels can increase for numerous reasons, ranging from minor infections to serious chronic diseases, making it a valuable but non-specific marker of inflammation throughout your body.

Acute infections: Bacterial infections typically cause the highest CRP elevations, often reaching levels above 100 mg/L. Common infections like pneumonia, urinary tract infections, or skin infections can elevate CRP levels.
Viral infections: Whilst generally causing lower CRP increases than bacterial infections, viruses can still elevate CRP levels, particularly in cases like influenza or COVID-19.
Tissue damage: Surgery, trauma, burns, or injuries can cause tissue damage that triggers inflammatory responses, leading to elevated CRP levels.
Chronic inflammatory conditions: Autoimmune diseases like rheumatoid arthritis, inflammatory bowel disease, or lupus can cause CRP elevation that fluctuates with disease activity.
Cardiovascular inflammation: Low-grade chronic inflammation in blood vessels contributes to heart disease development, detectable through high-sensitivity CRP testing.
Lifestyle factors: Obesity, smoking, lack of exercise, inadequate recovery, and poor sleep can cause chronic low-grade inflammation reflected in mildly elevated CRP levels.

What Triggers Your CRP to Rise

CRP levels can increase for numerous reasons, ranging from minor infections to serious chronic diseases, making it a valuable but non-specific marker of inflammation throughout your body.

Acute infections: Bacterial infections typically cause the highest CRP elevations, often reaching levels above 100 mg/L. Common infections like pneumonia, urinary tract infections, or skin infections can elevate CRP levels.
Viral infections: Whilst generally causing lower CRP increases than bacterial infections, viruses can still elevate CRP levels, particularly in cases like influenza or COVID-19.
Tissue damage: Surgery, trauma, burns, or injuries can cause tissue damage that triggers inflammatory responses, leading to elevated CRP levels.
Chronic inflammatory conditions: Autoimmune diseases like rheumatoid arthritis, inflammatory bowel disease, or lupus can cause CRP elevation that fluctuates with disease activity.
Cardiovascular inflammation: Low-grade chronic inflammation in blood vessels contributes to heart disease development, detectable through high-sensitivity CRP testing.
Lifestyle factors: Obesity, smoking, lack of exercise, inadequate recovery, and poor sleep can cause chronic low-grade inflammation reflected in mildly elevated CRP levels.

What Triggers Your CRP to Rise

CRP levels can increase for numerous reasons, ranging from minor infections to serious chronic diseases, making it a valuable but non-specific marker of inflammation throughout your body.

Acute infections: Bacterial infections typically cause the highest CRP elevations, often reaching levels above 100 mg/L. Common infections like pneumonia, urinary tract infections, or skin infections can elevate CRP levels.
Viral infections: Whilst generally causing lower CRP increases than bacterial infections, viruses can still elevate CRP levels, particularly in cases like influenza or COVID-19.
Tissue damage: Surgery, trauma, burns, or injuries can cause tissue damage that triggers inflammatory responses, leading to elevated CRP levels.
Chronic inflammatory conditions: Autoimmune diseases like rheumatoid arthritis, inflammatory bowel disease, or lupus can cause CRP elevation that fluctuates with disease activity.
Cardiovascular inflammation: Low-grade chronic inflammation in blood vessels contributes to heart disease development, detectable through high-sensitivity CRP testing.
Lifestyle factors: Obesity, smoking, lack of exercise, inadequate recovery, and poor sleep can cause chronic low-grade inflammation reflected in mildly elevated CRP levels.

When High CRP Signals Problems

While CRP elevation often indicates treatable conditions, very high levels or concerning patterns can signal serious problems requiring medical attention.

Severe infections: CRP levels above 100 mg/L often indicate severe bacterial infections, which are usually accompanied by symptoms. These levels are usually found in people who attend hospital.
Inflammatory disease flares: Sudden CRP increases in people with known inflammatory conditions like rheumatoid arthritis may indicate disease flares requiring treatment adjustment.
Hidden infections: Persistent significantly elevated CRP without obvious cause may indicate hidden infections or a source of inflammation in the body, sometimes requiring further investigation.

When High CRP Signals Problems

While CRP elevation often indicates treatable conditions, very high levels or concerning patterns can signal serious problems requiring medical attention.

Severe infections: CRP levels above 100 mg/L often indicate severe bacterial infections, which are usually accompanied by symptoms. These levels are usually found in people who attend hospital.
Inflammatory disease flares: Sudden CRP increases in people with known inflammatory conditions like rheumatoid arthritis may indicate disease flares requiring treatment adjustment.
Hidden infections: Persistent significantly elevated CRP without obvious cause may indicate hidden infections or a source of inflammation in the body, sometimes requiring further investigation.

When High CRP Signals Problems

While CRP elevation often indicates treatable conditions, very high levels or concerning patterns can signal serious problems requiring medical attention.

Severe infections: CRP levels above 100 mg/L often indicate severe bacterial infections, which are usually accompanied by symptoms. These levels are usually found in people who attend hospital.
Inflammatory disease flares: Sudden CRP increases in people with known inflammatory conditions like rheumatoid arthritis may indicate disease flares requiring treatment adjustment.
Hidden infections: Persistent significantly elevated CRP without obvious cause may indicate hidden infections or a source of inflammation in the body, sometimes requiring further investigation.

Understanding CRP vs. High-Sensitivity CRP

Two different CRP tests serve different purposes in medical care, and understanding the distinction helps explain why doctors might order one versus the other.

Standard CRP testing: This measures CRP levels typically above 3 mg/L and is used primarily to detect and monitor acute infections and inflammatory diseases.
High-sensitivity CRP (hs-CRP): This more sensitive test can detect CRP levels as low as 0.1 mg/L and is used for cardiovascular risk assessment without the context of looking for inflammation related to symptoms. It identifies low-grade chronic inflammation linked to heart disease risk.

Cardiovascular risk stratification: hs-CRP levels below 1 mg/L indicate low cardiovascular risk, 1-3 mg/L suggest moderate risk, and above 3 mg/L indicate high risk, helping doctors assess need for preventive strategies.

Understanding CRP vs. High-Sensitivity CRP

Two different CRP tests serve different purposes in medical care, and understanding the distinction helps explain why doctors might order one versus the other.

Standard CRP testing: This measures CRP levels typically above 3 mg/L and is used primarily to detect and monitor acute infections and inflammatory diseases.
High-sensitivity CRP (hs-CRP): This more sensitive test can detect CRP levels as low as 0.1 mg/L and is used for cardiovascular risk assessment without the context of looking for inflammation related to symptoms. It identifies low-grade chronic inflammation linked to heart disease risk.

Understanding CRP vs. High-Sensitivity CRP

Two different CRP tests serve different purposes in medical care, and understanding the distinction helps explain why doctors might order one versus the other.

Standard CRP testing: This measures CRP levels typically above 3 mg/L and is used primarily to detect and monitor acute infections and inflammatory diseases.
High-sensitivity CRP (hs-CRP): This more sensitive test can detect CRP levels as low as 0.1 mg/L and is used for cardiovascular risk assessment without the context of looking for inflammation related to symptoms. It identifies low-grade chronic inflammation linked to heart disease risk.

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Understanding Your Results

Understanding CRP interpretation helps you better comprehend what your results indicate and what steps might follow.

For standard CRP levels (not high sensitivity):

Normal levels: For standard CRP, levels below 5 mg/L are generally considered normal, indicating minimal inflammation.
Mild elevation (5-10 mg/L): Often indicates minor infections, mild inflammation, or possible evidence of a known chronic disease. These levels typically warrant clinical correlation with symptoms.
Moderate elevation (10-100 mg/L): Suggests bacterial infection, inflammatory disease flare, or a viral illness. Usually this will correlate with symptoms, but if not, monitoring is required depending on the degree of elevation.
High elevation (above 100 mg/L): Indicates more severe infection, tissue damage, or inflammatory conditions usually undergoing medical treatment.

For hs-CRP, the reference ranges in the context of cardiovascular and metabolic risk are:

Low risk: < 1mg/L
Average risk: 1-3 mg/L
Higher risk: > 3 mg/L

Changes in CRP levels over time are often more important than single values, helping doctors monitor treatment response and disease progression.

Doctors always interpret CRP results alongside symptoms, physical examination, and other tests, as CRP alone cannot diagnose specific conditions.

Understanding Your Results

Understanding CRP interpretation helps you better comprehend what your results indicate and what steps might follow.

For standard CRP levels (not high sensitivity):

Normal levels: For standard CRP, levels below 5 mg/L are generally considered normal, indicating minimal inflammation.
Mild elevation (5-10 mg/L): Often indicates minor infections, mild inflammation, or possible evidence of a known chronic disease. These levels typically warrant clinical correlation with symptoms.
Moderate elevation (10-100 mg/L): Suggests bacterial infection, inflammatory disease flare, or a viral illness. Usually this will correlate with symptoms, but if not, monitoring is required depending on the degree of elevation.
High elevation (above 100 mg/L): Indicates more severe infection, tissue damage, or inflammatory conditions usually undergoing medical treatment.

For hs-CRP, the reference ranges in the context of cardiovascular and metabolic risk are:

Low risk: < 1mg/L
Average risk: 1-3 mg/L
Higher risk: > 3 mg/L

Changes in CRP levels over time are often more important than single values, helping doctors monitor treatment response and disease progression.

Doctors always interpret CRP results alongside symptoms, physical examination, and other tests, as CRP alone cannot diagnose specific conditions.

Understanding Your Results

Understanding CRP interpretation helps you better comprehend what your results indicate and what steps might follow.

For standard CRP levels (not high sensitivity):

Normal levels: For standard CRP, levels below 5 mg/L are generally considered normal, indicating minimal inflammation.
Mild elevation (5-10 mg/L): Often indicates minor infections, mild inflammation, or possible evidence of a known chronic disease. These levels typically warrant clinical correlation with symptoms.
Moderate elevation (10-100 mg/L): Suggests bacterial infection, inflammatory disease flare, or a viral illness. Usually this will correlate with symptoms, but if not, monitoring is required depending on the degree of elevation.
High elevation (above 100 mg/L): Indicates more severe infection, tissue damage, or inflammatory conditions usually undergoing medical treatment.

For hs-CRP, the reference ranges in the context of cardiovascular and metabolic risk are:

Low risk: < 1mg/L
Average risk: 1-3 mg/L
Higher risk: > 3 mg/L

Changes in CRP levels over time are often more important than single values, helping doctors monitor treatment response and disease progression.

Doctors always interpret CRP results alongside symptoms, physical examination, and other tests, as CRP alone cannot diagnose specific conditions.

The Takeaway

CRP serves as a valuable marker of inflammation throughout your body, helping doctors detect infections, monitor chronic diseases, and assess cardiovascular risk. While elevated levels don't indicate specific diagnoses, they provide crucial information about inflammatory processes that may require medical attention.

Understanding CRP helps you appreciate why doctors use it alongside other tests and clinical assessment to make diagnoses and guide treatment decisions. For preventive health, low grade levels of inflammation may be a call to action to improve recovery, dietary quality, and exercise.

The Takeaway

References

Ridker, P. M. (2003). C-Reactive Protein: A Simple Test to Help Predict Risk of Heart Attack and Stroke. Circulation, 108(12)
British Society for Rheumatology. (2020). C-reactive protein in inflammatory disease assessment. Rheumatology Journal.
European Society of Cardiology. (2021). Biomarkers in cardiovascular disease. ESC Clinical Practice Guidelines.

References

Ridker, P. M. (2003). C-Reactive Protein: A Simple Test to Help Predict Risk of Heart Attack and Stroke. Circulation, 108(12)
British Society for Rheumatology. (2020). C-reactive protein in inflammatory disease assessment. Rheumatology Journal.
European Society of Cardiology. (2021). Biomarkers in cardiovascular disease. ESC Clinical Practice Guidelines.

References

Ridker, P. M. (2003). C-Reactive Protein: A Simple Test to Help Predict Risk of Heart Attack and Stroke. Circulation, 108(12)
British Society for Rheumatology. (2020). C-reactive protein in inflammatory disease assessment. Rheumatology Journal.
European Society of Cardiology. (2021). Biomarkers in cardiovascular disease. ESC Clinical Practice Guidelines.