C Reactive Protein Test (CRP Test)

C - Reactive Protein (CRP) Test Overview

The C-reactive protein test helps to measure the reactive protein levels in the blood. C-Reactive Protein, an acute phase reactant, is a pentameric protein found in blood whose circulating concentrations increase inflammatory reaction. 

CRP is a protein which is produced by the liver whenever there is inflammation in the body. Whenever there is inflammation in the body, its levels rise quickly, and also its level falls quickly on removal of the inflammatory stimulus.

Whenever there is chronic inflammation in the body in conditions such as chronic infections, CRP levels are persistently elevated. It is a very nonspecific test, and its levels can be elevated in any inflammatory condition. 

It binds to lysophosphatidylcholine expressed on the surface of dead or dying cells and some strains of bacteria. This binding then activates the complement system and promotes phagocytosis by macrophages to clear the dead cells/bacteria. It is vital to undergo the CRP blood test at the right lab for better results. 

Why is the C-Reactive protein test (CRP Test) prescribed?

CRP plays a role in innate immunity as an early defence system against infections. CRP level (hs-CRP or high sensitivity CRP) is an independent risk factor for atherosclerotic disease, hence used as a risk factor for cardiovascular disease (stroke, myocardial infarction and peripheral vascular disease).
Elevated levels are also seen in IBD, colon cancer, obstructive sleep apnoea, avian influenza, etc. The doctor will prescribe C reactive protein test to check the overall health condition.

What are the components of this test?

There are two types of CRP test: the standard CRP test and the high-sensitivity C-reactive protein test (hs-CRP). The hs-CRP test is highly sensitive and thus detects even a slight increase in CRP levels. This test is usually used to determine the risk of developing coronary artery disease.

Reference range

Biological Reference range- < 0.5mg/dl

The reference range varies from laboratory to laboratory. Your doctor would offer you the complete reference of the report, along with the required medication and diet that could help in keeping the CRP at a normal level.

Preparation and Perquisites

To prepare for the CRP blood test, you need to mention to your doctor the medication you are taking. Besides, you will need to do the fasting for 12 hours before the test, since eating food usually raises the CRP levels. If you are facing any inflammation or health issues, do mention them before the CRP blood test. 

The procedure for the C-reactive protein blood test is quick and short. Your clinician would inform you before the test.