C-Reactive Protein (CRP) Test - Quantitative

The C-reactive protein belongs to a class of proteins known as acute phase reactants. The acute-phase reactant increases in response to inflammatory conditions. 

When the body is under threat by infection or other conditions, the liver releases CRP into the bloodstream. It is the body's defence mechanism against cellular intruders. CRP levels are responses to inflammatory reactions.

Chronic illnesses like autoimmune diseases might trigger the acute phase response. CRP is a positive acute-phase reactant since it is an early responder. 

The CRP levels help doctors understand the severity of the inflammatory process, and the levels do not indicate the location of the inflammation. 

Types of CRP tests:

There are two types of CRP tests.

Qualitative CRP test

CRP qualitative levels might indicate inflammatory conditions. It is a parameter for assessing the severity of the inflammatory reaction. 

It determines whether C-reactive protein is under the normal limit or above that. It is a strip test. The results will be positive, indicating CRP is above the normal range. A negative test is an indication of CRP within normal limits.

This test also helps in the follow-up of medical treatment.

Quantitative CRP test

CRP quantitative test measures the levels of CRP in the blood. Quantitative CRP determines the presence of inflammatory response. Increasing quantitative CRP indicates a severe inflammatory reaction. Declining levels of CRP indicate recovery from inflammation.

So CRP quantitative tests monitor the treatment and progress of underlying disease conditions.

CRP is a non-specific test. It cannot diagnose underlying disease conditions.

The CRP test can detect flare-ups in a chronic inflammatory illness and track the patient's response to treatment.

The High Sensitivity C-reactive Protein Test (hs-CRP) is a type of CRP test that is more sensitive than the regular CRP test. High-sensitivity CRP (hs-CRP) testing can detect extremely low CRP levels. The hs-CRP test commonly assesses the risk of developing cardiovascular disease in otherwise healthy people. Even though both tests measure CRP, hs-CRP is considered a different test. 

Women tend to have slightly higher CRP levels compared to men. Pregnant women, too, show higher CRP levels.

Other names of CRP 

• CRP (quantitative) test
• C Reactive Protein Test 

What does the CRP test detect/measure and whom is this prescribed for?

The CRP quantitative test measures the exact value of C-reactive protein in blood samples.

The liver produces and secretes C-reactive protein (CRP) in reaction to any inflammation in the body. 

There is an elevation in CRP levels before the onset of acute inflammatory conditions. CRP test is suggested in people presenting acute inflammatory signs such as:

• High fever
• Increased heart rate
• Excessive sweating
• Shaking or trembling
• Persistent vomiting
• Acute diarrhoea
• Breathlessness
• Sudden rash or hives on the skin
• Swollen mouth or tongue
• Swollen or rashes on lips
• Dizziness 
• Vertigo
• Severe body pain
• Muscle soreness
• Loss of consciousness

CRP test is suggested in people with chronic inflammatory signs such as:

• Pain
• Frequent exhaustion
• Muscle stiffness and soreness
• Low-grade fever
• Chills with or without fever
• Frequent headaches
• Nausea and indigestion
• Sleeplessness or insomnia
• Unexplained weight loss
• Obesity
• Joint stiffness

If the doctor suspects any of the above diseases, he may ask for a CRP test. CRP test also detects the severity of the inflammatory condition. Doctors also suggest CRP tests to monitor the line of treatment in the above-listed disorders.

CRP levels in the blood decrease with a decrease in inflammation.

Some disease conditions for which CRP test is prescribed are:

• Atherosclerosis
• Irritable bowel syndrome
• Tissue injury
• Autoimmune diseases
• Post-surgery 
• After physical trauma
• Heart attack
• Infections
• Sepsis
• Cancer
• Infection caused by bacteria or viruses
• Rheumatoid arthritis

The CRP test is applicable for males and females, both adults and children. Some medicines, sleeplessness and obesity may give false elevation in CRP levels. Inform about ongoing medications to the doctor.

The results of C reactive protein test are based on the analysis of blood samples. A blood sample can be collected at a hospital or laboratory.

CRP Test Preparation

There is no need to prepare for the test, as it's a simple blood test. However, the doctor may ask you to fast for 9-12 hours before the sample collection, if you need to get other tests done that require fasting.

C- reactive protein test inclusions: What are the parameters included?

CRP test includes parameters of the quantity of C reactive protein. Quantitative CRP test results give the exact value of C-reactive proteins in the blood.

There is only one parameter included in the CRP test. This value gives an idea about the inflammatory response of the body. Various values of CRP levels can give a clue about what could be the underlying cause. CRP levels indicate the presence of infection or injury.

If there is no inflammation in the body, the values will be within normal limits. CRP levels are used to monitor the treatment of infections.

If the body is fighting infection or recovering from trauma, values of CRP will be higher.

In acute conditions, with weak defence and low recovery rate, CRP values will be abnormally high for a longer duration.

CRP quantitative tests measure C-reactive protein levels in blood samples.

The standard normal range of CRP is as follows:

• Recent injury or sickness can cause artificially elevated results.
• Mild CRP elevation can be there without any systemic or inflammatory illness.
• CRP levels are slightly higher in females and the elderly.
• Obesity, sleeplessness, pregnancy and smoking can all cause minor CRP levels.

• Certain medications, such as non-selective nonsteroidal anti-inflammatory drugs (Naproxen) can cause false low CRP levels.
• Magnesium supplements can lower CRP levels.

Therefore in people with these conditions, results should be interpreted carefully.

The test's normal values and reference ranges may vary from lab to lab. Please refer to the ranges mentioned in the report and consult a doctor to understand the interpretation of lab reports.

After collecting samples, it may take some time for the results to arrive. The doctor is the person who can explain the results appropriately. A qualitative CRP-positive test result indicates increased CRP levels in the blood.

Increased levels of CRP indicate inflammation, which could result from an infection, trauma, autoimmune illnesses, malignancies and other factors.

The CRP within normal limits is present in most healthy adults.

Mild elevation in CRP levels may be due to:

• Diabetes
• Common cold
• Gingivitis
• Periodontitis
• Sedentary lifestyle
• Cigarette smoking
• Genetic polymorphisms
• Obesity

Moderate elevation in CRP levels indicates:

• Systemic inflammatory conditions
• Rheumatoid arthritis
• Systemic lupus erythematosus
• Autoimmune diseases
• Malignancies (cancer)
• Myocardial infarction (heart attack)
• Pancreatitis
• Bronchitis

Marked elevation in CRP levels indicates:

• Acute bacterial infections
• Viral infections like COVID-19
• Systemic vasculitis
• Major trauma

Severe elevations of more than 50.0 mg/ dl are the result of acute bacterial infections.

Only the existence of an inflammatory condition can be detected using the CRP test. To identify the underlying diseases, additional tests and physical examinations are needed.

Rheumatoid Arthritis, Lupus Erythematosus, Sepsis, Cancer, Viral Infections

The price of a C-reactive protein (CRP) Test can fluctuate based on the location and chosen laboratory. Generally, the cost of a CRP test falls within the range of INR 380 to 1049. Let's take a look at the average cost of a CBC test in some major cities in India: