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Background <p>Dengue fever is an expanding public health threat in sub-Saharan Africa, yet access to laboratory-confirmed diagnosis remains severely constrained in resource-limited settings. Rapid diagnostic tests (RDTs) offer a practical alternative to molecular and serological diagnostic methods, but their performance must be validated in local epidemiological contexts before integration into national testing algorithms.</p> Methods <p>We conducted a retrospective laboratory-based diagnostic accuracy study using 221 archived serum samples from suspected dengue patients admitted to public and private hospitals in Niamey between October and December 2023. The STANDARD™ Q Dengue DUO (SD Biosensor) was compared against qRT-PCR (NS1 reference) and ELISA IgM (IgM reference). Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated with 95% Wilson score confidence intervals. Performance was stratified by viral load (Ct value) and time since symptom onset.</p> Results <p>Dengue infection was confirmed in 68/221 (30.8%) samples by qRT-PCR and 69/221 (31.2%) by IgM ELISA. For NS1 detection, the STANDARD™ Q demonstrated sensitivity of 79.4% (95% CI: 68.4–87.3%) and specificity of 85.5% (95% CI: 78.0–90.7%), with sensitivity increasing to 83.8% when combined with IgM. NS1 sensitivity was highest in samples with low and moderate viral load (Ct 20–30: 100%). NS1 sensitivity was 84.4% in the acute phase (≤ 7 days) versus 57.1% in the recovery phase (&gt; 7 days). For IgM detection, sensitivity was 49.3% (95% CI: 38.2–60.4%) but specificity was 98.6% (95% CI: 95.0–99.6%), with IgM sensitivity rising to 100% in the recovery phase.</p> Conclusion <p>The STANDARD™ Q Dengue DUO demonstrated adequate NS1 accuracy and high IgM specificity. Combined NS1 and IgM testing improves case detection across infection phases. Thus, we recommend this RDT as a first-line diagnostic tool in decentralized healthcare settings in Niger, although molecular testing remains essential for surveillance and serotyping purposes.</p>

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Diagnostic performance of the STANDARD™ Q Dengue DUO rapid diagnostic test in a resource-limited setting: a laboratory-based evaluation in the Republic of Niger

  • 期刊论文

  • 出版模式：

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  • 发表日期：

    2026年8月3日

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  • Adamou Lagare,
  • Nassirou Seyni Hamani,
  • Fatimata Hassane,
  • Hadiza Ousmane,
  • Absatou Daouda Ousseini,
  • Balki Aoula,
  • Moussa Issa,
  • Hassane Ousmane,
  • Abdullahi Balarabe Sallau,
  • Aliyu Muhammad

摘要

Background

Dengue fever is an expanding public health threat in sub-Saharan Africa, yet access to laboratory-confirmed diagnosis remains severely constrained in resource-limited settings. Rapid diagnostic tests (RDTs) offer a practical alternative to molecular and serological diagnostic methods, but their performance must be validated in local epidemiological contexts before integration into national testing algorithms.

Methods

We conducted a retrospective laboratory-based diagnostic accuracy study using 221 archived serum samples from suspected dengue patients admitted to public and private hospitals in Niamey between October and December 2023. The STANDARD™ Q Dengue DUO (SD Biosensor) was compared against qRT-PCR (NS1 reference) and ELISA IgM (IgM reference). Sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated with 95% Wilson score confidence intervals. Performance was stratified by viral load (Ct value) and time since symptom onset.

Results

Dengue infection was confirmed in 68/221 (30.8%) samples by qRT-PCR and 69/221 (31.2%) by IgM ELISA. For NS1 detection, the STANDARD™ Q demonstrated sensitivity of 79.4% (95% CI: 68.4–87.3%) and specificity of 85.5% (95% CI: 78.0–90.7%), with sensitivity increasing to 83.8% when combined with IgM. NS1 sensitivity was highest in samples with low and moderate viral load (Ct 20–30: 100%). NS1 sensitivity was 84.4% in the acute phase (≤ 7 days) versus 57.1% in the recovery phase (> 7 days). For IgM detection, sensitivity was 49.3% (95% CI: 38.2–60.4%) but specificity was 98.6% (95% CI: 95.0–99.6%), with IgM sensitivity rising to 100% in the recovery phase.

Conclusion

The STANDARD™ Q Dengue DUO demonstrated adequate NS1 accuracy and high IgM specificity. Combined NS1 and IgM testing improves case detection across infection phases. Thus, we recommend this RDT as a first-line diagnostic tool in decentralized healthcare settings in Niger, although molecular testing remains essential for surveillance and serotyping purposes.