title: Detection of dengue nonstructural 1 (NS1) protein in Vietnamese patients with fever.
abstract: Diagnosing dengue in febrile patients is challenging. Of a total of 459 patients with acute undifferentiated fever, randomly selected from 12 primary health facilities and 1 clinic of the provincial malaria station in southern Vietnam, dengue-specific antibody (Ab) and NS1Ag enzyme-linked immunosorbent assay (ELISA) (Platelia, Bio-Rad Laboratories, Hercules, CA 94547, US) were performed on acute (t0) and convalescent (t3 weeks) sera. Polymerase chain reaction (PCR) was used for confirmation. Based on a composite of the NS1Ag-ELISA, Ab-ELISA, and PCR results, 54 (12%) patients had acute dengue. Positive and negative predictive values were 65% and 98% for the Ab-based diagnosis and 91% and 92% for NS1Ag, respectively. The agreement between Ab- and NS1Ag-based diagnosis was poor (kappa value, 0.2). Two patients without dengue had detectable NS1Ag on t0 and t3, 1 just above the cutoff value and 1 with very high values. For 5 dengue patients, NS1Ag was still detectable at very high levels at t3. Dengue NS1Ag can be used for early diagnosis of dengue; infrequent false-positive results need further clarification.
authors.affiliation: Division of Infectious Diseases, Tropical Medicine and AIDS, Academic Medical Center, Amsterdam, The Netherlands.
authors.forename: Hoang Lan
authors.initials: HL
authors.lastname: Phuong
authors.forename: Khoa T D
authors.initials: KT
authors.lastname: Thai
authors.forename: Tran T T
authors.initials: TT
authors.lastname: Nga
authors.forename: Phan T
authors.initials: PT
authors.lastname: Giao
authors.forename: Le Q
authors.initials: le Q
authors.lastname: Hung
authors.forename: Tran Q
authors.initials: TQ
authors.lastname: Binh
authors.forename: Nguyen V
authors.initials: NV
authors.lastname: Nam
authors.forename: Jan
authors.initials: J
authors.lastname: Groen
authors.forename: Peter J
authors.initials: PJ
authors.lastname: de Vries
mesh_terms: D000293:Adolescent; D000328:Adult; D000914:Antibodies, Viral / Q000097:blood; D002648:Child; D003715:Dengue / Q000175:diagnosis*; D003716:Dengue Virus / Q000276:immunology / Q000302:isolation & purification*; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005260:Female; D005335:Fever of Unknown Origin / Q000821:virology*; D006801:Humans; D008297:Male; D011237:Predictive Value of Tests; D012367:RNA, Viral / Q000097:blood; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D013223:Statistics as Topic; D014744:Vietnam; D017361:Viral Nonstructural Proteins / Q000097:blood*; D055815:Young Adult
chemical_list: D000914:Antibodies, Viral; C079340:NS1 protein, Dengue virus type 2; C082515:NS1 protein, dengue-1 virus; D012367:RNA, Viral; D017361:Viral Nonstructural Proteins