Dengue diagnosis is based on the symptoms presented by the person, as well as laboratory tests such as blood count, virus isolation and biochemical tests, for example. After testing, your doctor can check the type of virus and thus indicate the most appropriate treatment for the person. For example, if a fever occurs, accompanied by two or more of the symptoms listed above, it is recommended that you go to the emergency room for diagnostic testing and treatment to begin.
Dengue is a disease caused by the bite of the infected Aedes aegypti mosquito, which occurs most often in summer and in wetter areas due to the ease of development of the dengue mosquito. Find out how to identify the dengue mosquito.
- The physical examination consists of the doctor’s assessment of the symptoms described by the patient.
- Indicating a classic dengue:.
In the case of hemorrhagic dengue, symptoms may also include excessive bleeding, which usually manifests as red spots on the skin, bruising, and frequent bleeding of the nose or gums, for example.
Symptoms usually appear 4 to 7 days after the bite of the mosquito infected with the virus and begin with a fever greater than 38 degrees Celsius, but after a few hours they are accompanied by other symptoms. Therefore, in case of suspected blood, it is important to consult a doctor so that more specific tests can be done to confirm the diagnosis and start treatment quickly, since in more severe cases, the dengue virus can affect the liver and heart. Find out what the complications of dengue are.
The collar test is a type of quick test that checks the fragility of blood vessels and the tendency to bleed, and is often performed in cases of suspected conventional dengue or hemorrhagic fever. This test involves interrupting blood flow in the arm and observing the appearance of small red dots, with a higher risk of bleeding the higher the number of red dots observed.
Although it is part of the tests indicated by the World Health Organization for the diagnosis of dengue, the collar test can give false results when the person consumes drugs such as aspirin or corticosteroids or is in the pre or postmenopausal phase, for example. Understand how the loop test is performed.
Rapid tests to identify dengue are increasingly used to diagnose potential cases of virus infection, as it takes less than 20 minutes to determine whether the virus is present in the body and for how long due to antibody, IgG and IgM detection. . This way, it is possible to start treatment more quickly.
However, the rapid test also does not identify the presence of other mosquito-borne diseases in the dengue, such as Zika or Chikungunya, and therefore, your doctor may order a normal blood test to determine if you are also infected with these viruses. The quick trial is free and anyone can take it in the health centers of Brazil at any time, as it is not necessary to fast.
This test aims to identify the virus in the bloodstream and establish which serotype, allowing the differential diagnosis of other diseases caused by the bite of the same mosquito and with similar symptoms, in addition to allowing the doctor to initiate a more specific treatment.
Isolation is done by testing a blood sample, which should be taken as soon as the first symptoms appear. This blood sample is sent to the laboratory and, using molecular diagnostic techniques, such as PCR, it is possible to identify the presence of the dengue virus in the blood.
The serological test aims to diagnose the disease by concentrating IgM and IgG immunoglobulins in the blood, proteins whose concentration is modified in case of infection. The concentration of IgM increases as soon as the person comes into contact with the virus, while IgG increases thereafter, but still in the acute phase of the disease, and remains in large amounts in the blood, thus being a marker of the disease, as is specific to each type of infection. Learn more about IgM and IgG.
Serological tests are usually requested to complete the virus isolation test and blood should be taken approximately 6 days after the onset of symptoms, as this allows for a more accurate test of immunoglobulin levels.
The blood formula and coagulogram are also tests requested by your doctor to diagnose dengue, especially hemorrhagic dengue. The blood count usually displays varying amounts of leukocytes and there may be leukocytosis, which increases the amount of leukocytes, or leukopenia, which corresponds to a decrease in the amount of leukocytes in the blood.
In addition, an increase in the number of lymphocytes (lymphocytosis) is generally observed with the presence of atypical lymphocytes, in addition to thrombocytopenia, that is, when platelets are less than 100,000/mm3, when the reference value is between 150,000 and 450,000/mm3. Know the reference values of the blood formula.
The coagulogram, which is the test that verifies blood clotting capacity, is usually requested in case of suspected hemorrhagic dengue and an increase in prothrombin time, partial thromboplastin and thrombin time, as well as a decrease in fibrinogen may be observed. , prothrombin, factor VIII and factor XII, indicating that hemostamia does not occur as it should, confirming the diagnosis of hemorrhagic dengue.
The main biochemical tests requested are the measurement of albumin and liver enzymes TGO and TGP, indicating the degree of hepatic impairment and indicating a more advanced pathological state when these parameters are presented.
Usually, when dengue is already at a later stage, it is possible to observe a decrease in the concentration of albumin in the blood and the presence of albumin in the urine, in addition to an increase in blood TGO and TGP levels, indicating liver damage.