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A comparison of oral fluid and serum for the detection of rubella‐specific antibodies in a community study in Addis Ababa, Ethiopia
Author(s) -
Nokes D. James,
Nigatu Wondatir,
Abebe Almaz,
Messele Tsehaynesh,
Dejene Amare,
Enquselassie Fikre,
Vyse Andrew,
Brown David,
Cutts Felicity T.
Publication year - 1998
Publication title -
tropical medicine and international health
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.056
H-Index - 114
eISSN - 1365-3156
pISSN - 1360-2276
DOI - 10.1046/j.1365-3156.1998.00227.x
Subject(s) - medicine , rubella , antibody , vacutainer , age groups , immunology , gastroenterology , measles , demography , vaccination , sociology
Summary objective To assess the utility of oral fluid compared with serum for the determination of age‐prevalence of rubella‐specific antibodies in an urban African community setting. method Paired serum and oral fluid samples were collected from 439 individuals aged 0–49 years in Addis Ababa, Ethiopia, as part of a larger seroepidemiological survey in 1994. Oral fluid was sampled using a simple sponge device that was well accepted by subjects of all ages; venous blood was collected by Vacutainer system. We measured rubella‐specific antibodies in serum by the Radial Haemolysis (RH) test, supported by two confirmatory assays, and in oral fluid by IgG antibody‐capture radioimmunoassay (GACRIA). results Sensitivity and specificity of oral fluid results compared to serum were 89% and 76%, respectively. Sensitivity declined from 96% in age group 0–19 years to 90% in age group 20–29 and 78% in age group 30–49. Specificity was 86% in 0–9 year olds contrasting with 61% in older groups (10–49 years). The positive predictive value of an oral fluid sample was high in all age groups (range 92–100%), while the negative predictive value declined from ≥80% in those aged <10 years to <10% in those aged ≥30 years. Serum confirmatory tests suggested a proportion of false serum RH negatives, increasing with age, indicating a need to standardize serum as well as oral fluid tests. conclusion In the community setting of a developing country, oral fluid surveys could be useful to estimate age‐prevalence of rubella immunity and identify rubella‐susceptible children for follow‐up. Further work is required to simplify assays and sample processing, improve assay sensitivity and estimate assay specificity more precisely, and compare and standardise collection methods suitable for surveillance of a variety of childhood viral infections.