A CRP rapid test on a blood sample can be performed in the doctor’s office. The test result is immediately available and helps the doctor assess whether antibiotic treatment is required. Quick initiation of the right treatment can be critical for the patient.
Antibiotics CRP, or C-reactive protein, is a so-called acute-phase protein produced by the liver in response to inflammations, tissue destruction and infections. In infections, the CRP concentration in the blood rises quickly, within 6–12 hours. This makes CRP measurement a useful diagnostic tool.
Usually the test is used to distinguish between viral and bacterial infections. This is important with regard to quick initiation of the right treatment. With a few exceptions, high CRP concentrations are seen only in bacterial infections. This information also helps to decide whether antibiotics are needed, because they only work on bacteria.
CRP measurement has been in extensive use since the 1980s, particularly in the Nordic countries. Before this, the most common methods included ESR (erythrocyte sedimentation rate) and blood count, which are still in use.
“The CRP rapid test is superior to the traditional methods, because the doctor gets the result immediately. Of course, doctors do not base their decisions on this test alone. It's the patient’s overall clinical picture that counts, but CRP is nevertheless an important tool for the doctor,” says Aino Takala, Vice President in Business Development at Orion Diagnostica and a doctor herself.
Helps to diagnose
respiratory tract infections
Fever and flu are among the most common reasons for seeing the doctor, and diagnosing respiratory tract infections is a typical situation where CRP measurement is useful.
“Antibiotics are prescribed for most respiratory tract infections, even though we know that they are not always necessary. Self-help and symptomatic treatment are often enough. The use of QuikRead CRP test could help to reduce unnecessary use of antibiotics and the associated costs and possible adverse effects. In the worst case, excessive use of antibiotics can increase microbial resistance to antibiotics,” Dr Takala explains.
Rapid test
saves time
Until the late 1990s, only hospital laboratories performed CRP tests. Then the first point-of-care test was introduced for use in the doctor's office.
Finland was among the pioneers. Orion Diagnostica’s QuikRead system has been a forerunner in the field and has become increasingly popular since the beginning of the 2000s. International interest in CRP tests is increasing vigorously.
For a quick CRP test, blood taken from a fingertip is mixed with the buffer agent and the cuvette is placed in the device. The result will be ready in a minute.
According to Dr Takala, point-of-care CRP tests help to reduce pressures due to lack of time and resources at health centres, because the test can be performed near to the patient. She believes that the test could be used more extensively and efficiently by renewing health centre routines.
“For example, when a child comes to the health centre and the receptionist sees that the patient has flu and fever, the CRP test could be performed practically in the waiting room.”
Reliable result
in one minute
All that is needed for a QuikRead CRP test is a fingertip blood sample. The sample is put in a tube, and the tube is placed in a small measurement device. The measurement takes only about one minute. The CRP level in blood is displayed in milligrams per litre.
In bacterial infections the CRP level can often rise to 100 mg/l or more, while in viral diseases it is much lower, usually 10–40 ml/l.
“A clearly negative result gives the doctor more unambiguous information than, say, a blood count. The doctor knows immediately that the infection is not bacterial and antibiotics will not be needed. Of course, it is possible that a bacterial infection is at such an early stage that the CRP level has not risen yet. Normally the doctor will always ask the patient to come back if the condition becomes clearly worse,” Dr Takala says.
Detecting risks
of illnesses?
All in all, the biological significance of CRP is not fully known yet, and new uses have been identified in recent years. In a laboratory environment it is possible to detect so-called sensitive, or very low, CRP levels, which are believed to be a risk factor for many illnesses.
A CRP level that is chronically even slightly elevated is known today to increase the risk to develop coronary heart disease or stroke, diabetes or even depression.
Text Timo Nykänen | Photos Kari Hautala