Diagnosis

Influenza quick test

definition

The rapid flu test is used to quickly find a diagnosis if an influenza infection is suspected. It is also known as the influenza test or the flu-quick test.

According to the manufacturer's information, the test is intended to replace the doctor's visit, but doctors see this very critically, as the layman can hardly differentiate between colds, flu-like infections and actual flu.

A positive test result must be reported.

Indication for the rapid flu test - when does it make sense?

The rapid flu test makes it easier to diagnose an influenza infection.

There are now drugs that prevent the flu pathogens from multiplying and thus reduce the symptoms and duration of the illness.
Since these drugs only make sense if the flu is actually present and not a cold, their use should depend on an accurate diagnosis.
In addition, in order to be effective, they must be taken no later than 3 days after infection. This makes a quick diagnosis necessary.

The flu quick test is therefore useful when treatment with flu medication (more precisely: Neuraminidase inhibitors) it's planned. Especially since the flu drug Oseltamivir® can cause severe neurological side effects.

During an influenza epidemic, however, a test does not necessarily have to be carried out to detect if the patient has the classic symptoms of influenza. The test is useful outside of the flu season.

You might also be interested in: Medicines for the flu

Performing the flu quick test

The principle of the rapid flu test is based on the detection of the influenza antigens A and B.

A sterile cotton swab is inserted deep into the nostril or nasopharynx (observe manufacturer's instructions!) And turned so that secretion is absorbed with the pathogens.
The wetted cotton swab is swirled in the liquid in the sample tube so that the pathogens can be detached from the cotton wool.
This test liquid is dropped onto a test cassette on which an indicator with the corresponding antibody is bound. The antigens from the nasal secretions bind to the antibodies on the indicator paper.
This is followed by a color change if flu viruses are present so that the result can be read at a glance.

Evaluation of the flu quick test

After waiting 10 to 15 minutes, the quick flu test can be evaluated.

The positive result appears as a color change in the form of a purple or pink-colored line. If the result is negative, this line is missing or no color change can be seen. There is a control line for comparison. The representation is reminiscent of a pregnancy test.

How reliable is the quick flu test?

When carried out correctly, the rapid tests provide a fairly reliable result.

The gold standard for the detection of influenza viruses is the laboratory test, in which the genetic makeup of the virus is shown. It has a reliability of up to 98%.

The rapid flu tests give 80-85% correct results. Since the influenza viruses are only detectable for 3 to 4 days, a smear that is too late can lead to a false negative result.

Can the rapid test also be false positive?

Since the rapid flu test only shows 80-85% of a correct result, the probability that a false positive or false negative result will appear is 15-20%. If the test is used by laypeople at home, the risk of incorrect results due to potential application errors increases.

What cannot I test with the rapid flu test?

If the infection was more than 4 days ago, the flu quick test can no longer provide a reliable result. In addition, he can only detect the influenza virus strains A and B. It cannot be shown which influenza virus is involved.

The polymerase chain reaction, which detects the virus in laboratory tests, on the other hand, can determine the exact virus, e.g. also the swine flu or bird flu.

Learn more at:

Swine flu
Bird flu

Can I buy the rapid test from the pharmacy without a prescription?

You can buy the rapid test for influenza for around 15-18 € in the pharmacy. One pack often contains several test sets. As a rule, no prescription is required as this is a voluntary service.

Can you do the quick flu test at home?

The rapid test can be used in the family doctor's practice or at home. Laypeople should be careful not to injure the nasal septum when performing it.

How long does the quick flu test take?

The evaluation of the flu quick test takes about 10-15 minutes. However, the respective manufacturer's instructions for implementation and waiting time must be observed.

What does the quick flu test cost?

The private rapid test can be purchased online or at the pharmacy. The cost is 15-18 €.

The possibility of doing a quick test at the family doctor depends on whether the respective doctor offers it. The alternative to the rapid test is the laboratory test, which is usually paid for by the health insurance company.

Does the health insurance company take part in the quick flu test?

No, the rapid flu test is a private service that is not covered by statutory health insurance.

Alternative to the quick flu test?

Alternatively, the diagnosis or virus detection can be carried out via a laboratory test. The genetic material of the influenza virus can be diagnosed using a so-called polymerase chain reaction. However, this procedure takes considerably longer than the rapid test and is dependent on the workload of the laboratory.