Utility of rapid diagnostic kit tests for diagnosis of suspected dengue fever

Background: Dengue fever often presents as an undifferentiated febrile illness requiring a laboratory test for identification. Serological tests particularly on rapid kits for the detection of NS1Antigen, IgG and IgM antibodies are the most commonly performed test across the country.Methods: The serum samples of suspected dengue cases were tested by Rapid test kits for assessing all the three parameters as well as by ELISA for NS1 antigen test. The platelet count of the patients was obtained from automated coulter counter. The results thus obtained were analyzed in Excel format.Results: The serum samples from 304 suspected Dengue fever cases were received in the lab, of which 190 samples were positive either by rapid or ELISA and 176 when rapid card test was considered alone Highest seropositivity of dengue cases were observed in the age group of ≥60 years (79.2%) followed by 45-59 years (70.7%). On rapid test, 78 cases were NS1 antigen positive of which 60 cases were positive only for NS1 antigen. When NS1 rapid and ELISA tests when compared, 16 kit negative tests were positive on ELISA while 34 kit positive tests were ELISA negative.  Sensitivity, specificity, PPV and NPV when only NS1 was considered on rapid test kits when compared with ELISA were 78.9%, 87.8%, 63.8% and 93.8%. 33.5% of serologically positive cases of Dengue had low platelet count on admission while only among negative cases 17.2% had a low platelet.Conclusions: Rapid kits often show variable results thus needing a validation of them from end user. As a positive dengue test result is an essential prerequisite for diagnosis thus it is essential that for serological tests ELISA technique should be used for reporting. Thus, it also mandates more efforts at decentralization of NVBDCP to include both government and non government institutions.

Definitive tests for dengue fever: when and which should I use?

Dengue is a mosquito-borne viral disease that has established itself globally in both endemic and epidemic transmission cycles. While diagnostic decision-making for dengue is often guided by clinical judgement, definitive laboratory tests, including rapid point-of-care tests, have many advantages in the primary care setting. These include providing epidemiological data and diagnostic clarity for atypical cases, as well as contributing to patient education and compliance. This article discussed the types of diagnostic methods for dengue, when to use them and the appropriateness of each test. Viral detection diagnostic methods such as NS1 antigen assays are generally used within the first week of illness onset, whereas dengue serology testing is most appropriate after that time frame. Locally available rapid point-of-care tests, which include both assays in one convenient test kit, can enhance dengue diagnosis in an endemic setting.

A Study to Evaluate the Efficacy of Actim Partus (A Rapid Bedside Test) in the Prediction of Preterm Labor.

Objective: The objective of the study was to evaluate the efficacy of bedside test kits (Actim partus kit) based on detection of phosphorylated insulin-like growth factor binding protein-1(PIGFBP-1) in cervical secretions in predicting preterm delivery. Material and methods: Patients presenting with symptoms of preterm labor between 28 and 36 weeks of gestation were recruited. PIGFBP-1 bedside tests (Actim partus test) were performed. Managing obstetricians and patients were blinded to the PIGFBP-1 results. Tocolysis and steroid therapy were administered to all the recruited patients. Outcome data were collected after delivery. Results: Fifty patients were recruited into the study, the median [± standard deviation [SD] gestational age at delivery was 34.12 weeks (± 2.1 weeks) and 37.14 weeks (± 2.8 weeks), patient testing positive and negative for Actim partus test, respectively. A positive result was associated with significantly reduced admission-to-delivery interval. The median admission-to-delivery interval was 3.25 days in the group with positive PIGFBP-1 results while 6.97 days with a PIGFBP-1 result (p < 0.001). Sensitivity, specificity, positive predictive value and negative predictive value of Actim partus test is 72.22%, 90.6% 81.25% and 85.29%, respectively. Conclusion: Actim partus (IGFBP-1) tests are effective adjuvant bedside test kits for the prediction of preterm delivery in patients presenting with signs or symptoms of preterm labor. High negative predictive values have great value in avoiding unnecessary interventions.

Validation of Two Portable Instruments to Measure Iron Concentration in Groundwater in Rural Bangladesh.

Iron is ubiquitous in natural water sources used around the world for drinking and cooking. The health impact of chronic exposure to iron through water, which in groundwater sources can reach well above the World Health Organization’s defined aesthetic limit of 0.3 mg/L, is not currently understood. To quantify the impact of consumption of iron in groundwater on nutritional status, it is important to accurately assess naturally-occurring exposure levels among populations. In this study, the validity of iron quantification in water was evaluated using two portable instruments: the HACH DR/890 portable colorimeter (colorimeter) and HACH Iron test-kit, Model IR-18B (test-kit), by comparing field-based iron estimates for 25 tubewells located in northwestern Bangladesh with gold standard atomic absorption spectrophotometry analysis. Results of the study suggest that the HACH test-kit delivers more accurate point-of-use results across a wide range of iron concentrations under challenging field conditions.