From the Guidelines
The World Health Organization (WHO) minimum criteria for diagnosing dengue fever include fever and any two of the following: thrombocytopenia (platelet count ≤100,000 cells/mm³), hemorrhagic manifestations, or hepatomegaly 1.
Key Criteria
- Fever is a required criterion
- Any two of the following are also required:
- Thrombocytopenia (platelet count ≤100,000 cells/mm³)
- Hemorrhagic manifestations
- Hepatomegaly Specifically, the presence of fever and thrombocytopenia are essential components of the WHO minimum criteria for diagnosing dengue fever, as they are commonly observed in patients with dengue fever 1.
Laboratory Diagnosis
Laboratory diagnosis of dengue fever can be performed using various methods, including:
- Serology: Serum samples can be tested for the presence of dengue virus-specific antibodies 1
- NS1 antigen: Serum samples can be tested for the presence of the dengue virus NS1 antigen, which is secreted from infected host cells as early as 1 day after symptom onset and up to 10 days thereafter 1
- NAAT: Nucleic acid amplification tests (NAAT) can be used to detect dengue virus RNA in serum or plasma samples, and is preferred for acutely ill patients 1 It is worth noting that while these laboratory tests can aid in the diagnosis of dengue fever, they should be used in conjunction with clinical findings to confirm the diagnosis 1.
From the Research
Minimum Criteria for Diagnosing Dengue Fever
The World Health Organization (WHO) has established minimum criteria for diagnosing dengue fever. According to the studies 2, 3, 4, 5, 6, the WHO classification schemes for dengue have undergone revisions. The key criteria for diagnosing dengue fever include:
- Fever
- Any two of the following:
- Hemorrhagic manifestations (e.g., petechiae, bleeding gums, hematemesis)
- Plasma leakage (e.g., hemoconcentration, pleural effusion, ascites)
- Low platelet count (typically <100,000 cells/mm^3)
- Elevated hematocrit
Comparison of WHO Classification Schemes
The studies compared the effectiveness of different WHO classification schemes for dengue, including the 1997 and 2009 schemes 3, 5. The 2009 scheme categorizes dengue into three groups:
- Group A (without warning signs)
- Group B (with warning signs, such as abdominal pain, vomiting, or fluid accumulation)
- Group C (severe plasma leakage, severe bleeding, or organ failure)
Diagnostic Accuracy
The diagnostic accuracy of the WHO clinical definitions for dengue was assessed in a systematic review and meta-analysis 4. The results showed that the sensitivity of the 1997 and 2009 definitions was 93% and 93%, respectively, while the specificity was 29% and 31%, respectively.
Performance of Case Definitions
A comparative study evaluated the performance of the probable case definitions of dengue by WHO (2009) and the WHO-SEAR expert group (2011) 6. The results showed that the 2009 WHO case definition had a sensitivity of 76.4% and a negative predictive value of 87.5%, while the 2011 WHO-SEAR expert group case definition had a higher sensitivity of 87.9% but a lower negative predictive value of 86.6%.