How many days of fever do you test for dengue fever?

Patients with Dengue hemorrhagic fever often have the following signs:
High fever 39 - 41 degrees Celsius, sudden and continuous fever lasting from 2 to 7 days; Hemorrhage: Purulent spots appear on the skin, there may be nosebleeds, bleeding gums, vomiting blood, bloody or black stools, bruising at the injection site (if any); Abdominal pain (due to an enlarged liver); Pulse collapse: On the 3rd to 6th day, the patient usually has no fever, but is still lethargic or restless, cold hands and feet, purple lips, little urination, the patient can die quickly if the patient does not have dengue fever. get emergency treatment in a timely manner. If children have symptoms of high fever continuously for more than 2 days, it is necessary to urgently take them to medical examination and treatment facilities for timely examination.
Watch now: Dengue blood test indicators

The typical symptoms of dengue fever are fever and subcutaneous hemorrhage in the form of a rash. The most dangerous time of dengue fever occurs from day 3 to day 7 (from the time of onset first symptom of the disease). So how many days fever, dengue fever test?
Patients can take a dengue test (dengue test) from the 3rd day since the first fever appeared, ie the fever has been 3 days. However, during the outbreak of dengue fever, patients with sudden high fever symptoms should be tested earlier: about 24 - 48 hours after the first appearance of fever. It should be noted that if the test is performed too soon, a false negative may occur (i.e. have dengue fever but the test result is negative).

Patients with suspected dengue infection should have a complete blood count test. This test is used to monitor a patient's daily changing blood cell counts and diagnostic tests for viruses including dengue antigen and antibody tests.
3.1. Complete blood count The results of a complete blood count of a dengue patient often have thrombocytopenia. This is explained by the fact that during viral infection, the patient's body will produce antibodies against the virus, which inadvertently destroy the host platelets through the immune mechanism. At the same time, dengue virus can cause myelosuppression, thereby causing temporary thrombocytopenia. When platelets in the blood decrease, it will lead to bleeding such as: Hemorrhage under the skin in the form of a rash, mucosal bleeding (nosebleeds, bleeding gums, bleeding at the injection site...) . More serious is the condition of bleeding inside the body with recognizable signs such as: abdominal pain, vomiting blood, black stools, prolonged menorrhagia...
Patients with dengue fever have thrombocytopenia. The risk of bleeding should be rested in bed, avoid walking a lot, and limit surgical interventions (avoid touching large veins or veins that are difficult to stop bleeding such as the jugular, inguinal, and subclavian veins).
According to the latest regulations of the Ministry of Health of Vietnam in 2019, patients with dengue fever need to be transfused with platelets when the platelet count is below the threshold of 50 g/L and accompanied by bleeding symptoms. For patients with no symptoms of bleeding but with a platelet count less than 5 g/L, platelet transfusions should be performed.
3.2. Dengue NS1 antigen test The method is performed at the time of suspected dengue infection in the first 3 days. However, there is a feature to note that the concentration of Dengue NS1 antigen in the blood of patients often tends to decrease after the first 3 days, so if testing for antigens after this time will give results. false negative - the body has a virus infection but the result is negative, not sick.
3.3. IgG antibody test If the patient's history of dengue fever needs to be checked, the doctor will usually order a test for IgG antibodies. This test is not used to diagnose acute dengue fever since IgG antibodies will start to be present in the patient's body 7 days after the illness. They will survive and protect the body from the infected dengue virus for the rest of its life.
3.4. IgM antibody test This type of antibody test is applied to patients who have had symptoms of fever about 3-5 days since infection with the dengue virus. After entering the acute phase, the body's immune system will produce IgM antibodies. This antibody functions against the virus that causes dengue fever. Therefore, the patient's ability to generate IgM antibodies is a key factor in determining the test's results.
3.5. Other tests that aid in the diagnosis and treatment of dengue fever CRP test : this is a test done to assess the risk of bacterial superinfection with dengue fever; Albumin test: The liver is the organ responsible for the production of Albumin - a protein that plays a role in maintaining colloidal permeability in the blood, and at the same time, the liver also produces amino acids involved in the synthesis of proteins. cell. Albumin test is performed when detecting signs of Dengue virus infection to check the state of blood plasma spilling, thereby helping the doctor to come up with a suitable treatment plan; Electrolyte: This subclinical method has the effect of determining the levels of K+, Na+, and Cl- ions in the patient's body, helping to check whether electrolyte disturbances occur or not; Renal function test (Urea index test, Cystatin C, Creatinine, Microalbuminuria): assess the risk of complications or kidney damage caused by dengue fever; Liver function tests (measurement of liver enzymes GGT, ALT, AST): assess the risk of complications or liver damage from dengue disease. Laboratory tests to diagnose dengue should be done in the laboratory of the clinic or hospital, because the specimen is a blood sample. However, at present, dengue fever testing services at home of hospitals or clinics are being born more and more, bringing many conveniences to patients, the time to return results is similar to direct testing. at the hospital.
It can be seen that dengue fever is in season with the number of cases increasing rapidly in the community. Monitoring the symptoms of the disease and promptly performing dengue tests will help detect the disease early and have the most appropriate treatment.