Tubex, a fast and effective blood test to diagnose typhus

What is the TUBEX test?

When you experience symptoms of typhus (typhus) or typhoid fever, such as dizziness, stomach pain, and weakness, your doctor may perform a series of tests. The first step, the doctor will ask about medical history and travel.

This is important because typhus is transmitted through an unhygienic environment and habits. Next, the doctor will check your physical condition, from body temperature to see which part of your stomach hurts.

To confirm typhoid fever, the doctor will ask you to do a blood test. One method of examining your blood sample is called the TUBEX test.

The TUBEX test is a set of test kits to detect the presence of IgM anti-O9 antibodies in the blood. These antibodies are automatically generated by the immune system when the body is infected by bacteria that cause typhus, Salmonella typhi.

So, if the TUBEX test detects the presence of anti-O9 IgM antibodies in your blood sample, it means that you are diagnosed with typhus.

The test execution process

The TUBEX test can only be done in a clinic, hospital, or laboratory. The duration of the test is quite fast, only taking about 10 minutes for the final results to be known.

Before the test is carried out you do not need to make any preparations. The first stage of the TUBEX test, which is taking a blood sample may be uncomfortable for you,

Here's the TUBEX test procedure in the laboratory:

A laboratory technician will take a sample of your blood.
The technician will insert 45μl of magnetic particle antigen (Brown regeant) into each of the 6 test tubes.
Afterward, insert 45μl of the patient's blood sample into all test tubes.
Let stand for 2 minutes.
After 2 minutes, the technician will drop 90 µl of antibody-coated indicator particle (Blue reagent).
Cover each test tube using the special medical tape provided with the TUBEX device
The technician will then tilt the tube and shake it for 2 minutes. This aims to expand the reaction yield.
After 2 minutes, the tube was raised again and placed on the magnet .
Let stand upright for 5 minutes. This step is taken to start the deposition process.

A positive or negative diagnosis of typhoid fever from the TUBEX test can be seen from the color displayed on the tube. A positive test result is generally indicated in blue, meaning that there is no color change in the sample liquid. The blue color indicates that your blood sample contains anti-O9 IgM antibodies.

After confirming the diagnosis of typhus through these tests, the doctor will determine the right treatment for your condition. Most cases of typhus can be treated with antibiotics, such as azythromycin and ceftriaxone.

How effective is the TUBEX test?

The TUBEX test is a new breakthrough so that specific studies studying its effectiveness for diagnosing typhus are still very limited. However, a study published by Diagnostic Microbiology and Infectious Disease states that this test has a sensitivity of up to 91% with a specificity of 82%. Meanwhile, the Widal test has a sensitivity of 82% and a specificity of 58%.

Sensitivity and specificity are measures of the ability of a screening test to distinguish between sick and non-sick individuals. Sensitivity refers to how accurately the screening test recognizes disease in people who have the disease, categorized as "positive".

Meanwhile, specificity is a measure of the accuracy of the test to exclude people who did not have the disease, categorized as “negative”.

A screening test is said to be ideal if very sensitive and very specific. A very specific and very sensitive test means that there is very little chance of a negative / false positive result. Then there will be fewer cases of the disease being misdiagnosed.

Research published in the Journal of Medical Microbiology has even found that the TUBEX test can be used in several ways to diagnose typhus, namely:

Detection of antibodies and antigens from blood serum
Detection of antigens from urine to complete detection via serum
Detection or identification of all organisms from blood or fecal cultures

Although it looks promising, the results of this study require further research. The reason is, until now, the TUBEX test is still being carried out using blood serum.

The TUBEX test results proved to be more accurate than the Widal test. However, the Widal test is more widely used in Indonesia because of its lower price.

Getting an accurate typhus diagnosis can help you choose the right typhus treatment. By getting the right treatment, you can avoid the life-threatening complications of typhoid fever.