C-reactive protein

C-reactive protein (CRP)

CRP is an acute inflammatory protein produced by the liver in response to an infection, injury, or autoimmune process. It plays a key role in activating the immune systemby binding to pathogens and damaged cells to mark them for destruction.

DRR Main functions:

• Marker of inflammation (increases as early as 4-6 hours after the onset of inflammation).
• Participation in the immune response (activates the complement system).
• Prognostic indicator for cardiovascular diseases (highly sensitive CRP- hs-CRP).

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The norm of CRP in the blood

Category	Level (mg/L)	Interpretation
Healthy Individuals	< 5	Normal
Mild Inflammation	5–10	Possible chronic infection, smoking
Moderate Inflammation	10–50	Bacterial infections, exacerbation of autoimmune diseases
Severe Inflammation	> 50	Acute bacterial infections, sepsis, burns, trauma
hs-CRP (Cardiac Risk)	< 1	Low risk
	1–3	Moderate risk
	> 3	High risk of atherothrombosis

Note:

• In newborns, CRP can normally be up to 10 mg/l.
• After surgery or injury, the level temporarily increases.

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Deviations from the norm

1. Increased CRP (hyperproduction)

Reasons:

• Infections (bacterial > viral).
• Autoimmune diseases (rheumatoid arthritis, lupus, vasculitis).
• Injuries, burns, and surgeries.
• Oncology (lymphomas, carcinomas).
• Cardiovascular diseases (atherosclerosis, heart attack).

Symptoms of excess:
Depend on the underlying disease:

• Fever, weakness (with infections).
• Joint pain, rash (with autoimmune processes).
• Shortness of breath, chest pain (in case of a heart attack).
• Weight loss, night sweats (in cancer).

How dangerous is it?

• Chronically high CRP (> 10 mg / L) is associated with the risk of heart attack, stroke, and type 2 diabetes.

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2. Reduced DRR

CRP deficiency is an extremely rare condition, as it can normally be close to zero in healthy people.

Possible causes of artificial decline:

• Taking NSAIDs (ibuprofen, aspirin).
• Hormone therapy (statins, corticosteroids).
• Liver failure (impaired protein synthesis).

Symptoms of deficiency:
Non-specific, related to the underlying disease:

• Predisposition to infections (if the cause is immunodeficiency).
• Edema, jaundice (with liver diseases).

How dangerous is it?
Low CRP is not an independent pathology, but it can mask inflammation.

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What should I do if there are deviations?

If the DRR is increased:

1. Search for the cause – analysis on:

• White blood cells, ESR (confirmation of inflammation).
• Blood culture, PCR (infections).
• Rheumatoid factor, ADCC (autoimmune diseases).
• CT/MRI scan(if a tumor is suspected).

1. Treatment of the underlying disease (antibiotics, immunosuppressants).
2. Control of hs-CRP in cardiological patients.

If the DRR is lowered:

• It usually doesn’t require correction.
• In case of suspected immunodeficiency, consult an immunologist.

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Important!

• CRP is a non – specific marker: it does not indicate the exact cause of inflammation.
• HS-CRP is used to assess chronic inflammation (for example, in atherosclerosis) .
• The level of CRP decreases rapidly after the inflammation is eliminated (unlike ESR).

A doctor (general practitioner, rheumatologist, infectious diseases specialist) should prescribe and interpret the analysis.