Use of a three-band HRP2/pLDH combination rapid diagnostic test increases diagnostic specificity for falciparum malaria in Ugandan children

Michael Hawkes, Andrea L. Conroy, Robert O. Opoka, Sophie Namasopo, W. Conrad Liles, Chandy John, Kevin C. Kain

Research output: Contribution to journalArticle

24 Citations (Scopus)

Abstract

Background: Rapid diagnostic tests (RDTs) for malaria provide a practical alternative to light microscopy for malaria diagnosis in resource-limited settings. Three-band RDTs incorporating two parasite antigens may have enhanced diagnostic specificity, relative to two-band RDTs with a single parasite antigen (typically histidine-rich protein 2 [HRP2]). Methods. Phase 1: 2,000 children, two months to five years of age, admitted to a referral hospital in Jinja, Uganda, with acute febrile illness were enrolled. A WHO highly rated three-band RDT was compared to light microscopy of thick peripheral blood films read by local expert microscopists. Phase 2: the three-band RDT was used as a screening tool for inclusion of patients in a clinical trial, and subjects with three positive RDT bands were tested by microscopy using blood samples drawn in parallel. Discordant results were adjudicated by PCR. Results: Phase 1: 1,648 children had both a RDT and peripheral blood smear performed. The specificity of a RDT with all three bands positive was 82% (95% CI: 79-85%) compared to 62% (95% CI: 59-66%) for HRP2 alone. The sensitivity was 88% (95% CI: 85-89%) and 94% (95% CI: 92-95%) for three-band positive RDT and HRP2 antigen, respectively. 119 patients (7.2%) had a positive HRP2 band, but negative parasite lactate dehydrogenase (pLHD) band and negative peripheral smear, and 72 (61%) of these had received pre-treatment with anti-malarials, suggesting a false positive HRP2 result (p = 0.002). Phase 2: the positive predictive value (PPV) of the three-band RDT was 94% (95% CI 89%-97%) using microscopy as the reference standard. However, microscopy-discordant results were shown to be positive for P. falciparum by PCR in all cases, suggesting that the PPV was in fact higher. Conclusion: The pLDH antigen on three-band RDTs, used in combination with HRP2, provides added diagnostic specificity for malaria parasitaemia and may be useful to distinguish acute infection from recently treated infection. In situations where diagnostic specificity is desirable (e.g., for selection of malaria-infected participants in clinical trials), a three-band RDT should be considered in a sub-Saharan African setting.

Original languageEnglish (US)
Article number43
JournalMalaria Journal
Volume13
Issue number1
DOIs
StatePublished - Feb 1 2014
Externally publishedYes

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Falciparum Malaria
Routine Diagnostic Tests
Microscopy
Malaria
Antigens
Parasites
histidine-rich proteins
Clinical Trials
Light
Polymerase Chain Reaction
Uganda
Parasitemia
Antimalarials
Infection
L-Lactate Dehydrogenase
Fever
Referral and Consultation

Keywords

  • Malaria
  • Rapid diagnostic test
  • Sensitivity
  • Specificity

ASJC Scopus subject areas

  • Infectious Diseases
  • Parasitology

Cite this

Use of a three-band HRP2/pLDH combination rapid diagnostic test increases diagnostic specificity for falciparum malaria in Ugandan children. / Hawkes, Michael; Conroy, Andrea L.; Opoka, Robert O.; Namasopo, Sophie; Liles, W. Conrad; John, Chandy; Kain, Kevin C.

In: Malaria Journal, Vol. 13, No. 1, 43, 01.02.2014.

Research output: Contribution to journalArticle

Hawkes, Michael ; Conroy, Andrea L. ; Opoka, Robert O. ; Namasopo, Sophie ; Liles, W. Conrad ; John, Chandy ; Kain, Kevin C. / Use of a three-band HRP2/pLDH combination rapid diagnostic test increases diagnostic specificity for falciparum malaria in Ugandan children. In: Malaria Journal. 2014 ; Vol. 13, No. 1.
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abstract = "Background: Rapid diagnostic tests (RDTs) for malaria provide a practical alternative to light microscopy for malaria diagnosis in resource-limited settings. Three-band RDTs incorporating two parasite antigens may have enhanced diagnostic specificity, relative to two-band RDTs with a single parasite antigen (typically histidine-rich protein 2 [HRP2]). Methods. Phase 1: 2,000 children, two months to five years of age, admitted to a referral hospital in Jinja, Uganda, with acute febrile illness were enrolled. A WHO highly rated three-band RDT was compared to light microscopy of thick peripheral blood films read by local expert microscopists. Phase 2: the three-band RDT was used as a screening tool for inclusion of patients in a clinical trial, and subjects with three positive RDT bands were tested by microscopy using blood samples drawn in parallel. Discordant results were adjudicated by PCR. Results: Phase 1: 1,648 children had both a RDT and peripheral blood smear performed. The specificity of a RDT with all three bands positive was 82{\%} (95{\%} CI: 79-85{\%}) compared to 62{\%} (95{\%} CI: 59-66{\%}) for HRP2 alone. The sensitivity was 88{\%} (95{\%} CI: 85-89{\%}) and 94{\%} (95{\%} CI: 92-95{\%}) for three-band positive RDT and HRP2 antigen, respectively. 119 patients (7.2{\%}) had a positive HRP2 band, but negative parasite lactate dehydrogenase (pLHD) band and negative peripheral smear, and 72 (61{\%}) of these had received pre-treatment with anti-malarials, suggesting a false positive HRP2 result (p = 0.002). Phase 2: the positive predictive value (PPV) of the three-band RDT was 94{\%} (95{\%} CI 89{\%}-97{\%}) using microscopy as the reference standard. However, microscopy-discordant results were shown to be positive for P. falciparum by PCR in all cases, suggesting that the PPV was in fact higher. Conclusion: The pLDH antigen on three-band RDTs, used in combination with HRP2, provides added diagnostic specificity for malaria parasitaemia and may be useful to distinguish acute infection from recently treated infection. In situations where diagnostic specificity is desirable (e.g., for selection of malaria-infected participants in clinical trials), a three-band RDT should be considered in a sub-Saharan African setting.",
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AU - Liles, W. Conrad

AU - John, Chandy

AU - Kain, Kevin C.

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