scholarly journals Evaluating the use of microscopic examination and rapid diagnostic tests to diagnose malaria in North Central Nigeria

2014 ◽  
Vol 3 (1) ◽  
Author(s):  
Innocent C. Omalu ◽  
George Uzoaga ◽  
Israel Kayode Olayemi ◽  
Charles Mgbemena ◽  
Suleiman Hassan ◽  
...  

The global impact of malaria has spurred interest in developing prompt and accurate diagnostic strategies to provide an effective management of the disease. The aim of this study was to compare rapid diagnostic tests (RDTs) for malaria with routine microscopy. Samples were collected randomly from 364 febrile out-patients with clinical suspicion of malaria from four hospitals in North Central Nigeria. Results from the rapid diagnostic kits were analysed and compared to those obtained by general microscopy. Of the 364 out-patients involved in the study, 218 (59.89%) tested positive for <em>Plasmodium falciparum</em> by RDTs, whereas 263 (72.256%) tested positive by microscopy. There are significant differences (P&lt;0.05) in infection rates between RDT and microscopy. The sensitivity, specificity and negative predictive values of RDTs compared to microscopy are low, while the positive predictive value is high. Evaluation of RDTs against the parasite-positive panel with parasite densities of &lt;1000 parasites/μL, between 1000-5000 parasites/μL and above 5000 parasites/ μL was 11.73, 30.61, 57.65% for RDTs compared to 6.11, 27.95 and 65.94% for microscopy, respectively. Test line intensity increases with increase in parasite densities for both methods.

Author(s):  
Aneley Getahun Strobel ◽  
Stephanie Airs ◽  
Cattram Nguyen ◽  
Taina Rokobuli Vadei ◽  
Silivia Matanitobua ◽  
...  

Typhoid is an endemic in Fiji with increases observed since the early 2000s and frequent outbreaks reported. We assessed the diagnostic accuracy of currently available typhoid rapid diagnostic tests (RDTs) (TUBEX, Typhidot Rapid, and Test-It assay) to establish their performance against blood culture in Fiji and to examine their suitability for rapid typhoid outbreak identification. The performance of RDTs was assessed in the public health reference laboratory in Suva, Fiji, according to the manufacturers’ instructions. A simulation was used to examine the potential use of RDTs for attribution of a febrile illness outbreak to typhoid. For the diagnostic evaluation, 179 patients were included; 49 had blood culture–confirmed typhoid, 76 had fever as a result of non-typhoid etiologies, and 54 were age-matched community controls. The median (interquartile range) age was 29 (20–46) years. Of the participants, 92 (51.4%) were male and 131 (73.2%) were indigenous Fijians. The sensitivities of the tests were 77.6% for TUBEX, 75.5% for Typhidot Rapid, and 57.1% for Test-It assay. The Test-It assay had the highest specificity of 93.4%, followed by Typhidot Rapid 85.5% and TUBEX 60.5%. Typhidot Rapid had the best performance in the simulation for attribution of a febrile illness outbreak to typhoid. Typhoid RDTs performed suboptimally for individual patient diagnosis due to low sensitivity and variable specificity. We demonstrate that RDTs could be useful in the field for rapid attribution of febrile illness outbreaks to typhoid. Typhidot Rapid had the best combination of sensitivity, specificity, positive and negative predictive values, cost, and ease of use for this purpose.


2021 ◽  
Author(s):  
Sindew M. Feleke ◽  
Emily N. Reichert ◽  
Hussein Mohammed ◽  
Bokretsion G. Brhane ◽  
Kalkidan Mekete ◽  
...  

AbstractMalaria diagnostic testing in Africa is threatened by Plasmodium falciparum parasites lacking histidine-rich protein 2 (pfhrp2) and 3 (pfhrp3) genes. Among 12,572 subjects enrolled along Ethiopia’s borders with Eritrea, Sudan, and South Sudan and using multiple assays, we estimate HRP2-based rapid diagnostic tests would miss 9.7% (95% CI 8.5-11.1) of falciparum malaria cases due to pfhrp2 deletion. Established and novel genomic tools reveal distinct subtelomeric deletion patterns, well-established pfhrp3 deletions, and recent expansion of pfhrp2 deletion. Current diagnostic strategies need to be urgently reconsidered in Ethiopia, and expanded surveillance is needed throughout the Horn of Africa.


Blood ◽  
2018 ◽  
Vol 132 (Supplement 1) ◽  
pp. 5570-5570
Author(s):  
Gilda Zagoya ◽  
Alejandro Ruiz-Argüelles ◽  
Guillermo J. Ruiz-Arguelles

Abstract Introduction. In vitro laboratory tests to diagnose of plasma cell myeloma vary considerably in sensitivity, specificity and positive and negative predictive values. We compared the performance of quantification of free immunoglobulin light chains with other methods used to detect a monoclonal protein in serum and/or urine. Objective. Compare sensitivity, specificity and positive and negative predictive values of several in vitro laboratory tests to detect monoclonal proteins in serum and urine in persons with plasma cell myeloma. Methods. 70 subjects with plasma cell myeloma and 50 controls were studied. Diagnostic tests included: (1) quantification of free and total immunoglobulin light-chains by immune assays; (2) immune fixation of heavy-and light-chains in serum and urine after gel electrophoresis; and (3) serum protein capillary electrophoresis. Diagnosis of plasma cell myeloma was based on clinical and radiological criteria, bone marrow examination and flow cytometric immune phenotyping with monoclonal antibodies to CD56, CD19, CD138 (CD38) and CD45. Sensitivity, specificity and positive and negative predictive values for each tests were estimated from contingency tables. Results. Quantification of free immmunoglobulin light-chains had the highest sensitivity and specificity and best positive and negative predictive values. Immune fixation of serum immunoglobulins was next best. Quantification of total immunoglobulin light-chains was the least sensitive and specific with the worst positive and negative predictive values. Quantitation of free light-chains had the additional advantage of objectivity (independence from observer bias). The immune fixation test was the most subject to observer bias. Conclusion. Quantification of free immunoglobulin light-chains had the best sensitivity, specificity and positive and negative predictive values for diagnosing plasma cell myeloma. (Table 1) Disclosures No relevant conflicts of interest to declare.


2021 ◽  
Author(s):  
Loveness Mukuka ◽  
Andros Theo ◽  
Mowa Zambwe ◽  
Peter J Chipimo

Objective: To investigate the performance of the HIV RDTs used in Zambia. Method: 2,564 participants aged between 15 and 95 years from two sites in Lusaka province years were tested on OraQuick ADVANCE, Abbot Determine, and then confirmed on Uni-Gold Recombigen. The data from the participants were analyzed using SPSS version 25.0. Results: The 3 RDTs when compared to the 4th generation Abbot Architect results had the following results: OraQuick ADVANCE, Alere Determine and Uni-Gold Ultra, at 95% CI had Sensitivities of: 91.8%, 93.3% and 92.5% respectively. The specificities of OraQuick ADVANCE and Uni-Gold were the same (100.0%; 95% CI: 98.8 -100.0) but slightly different from Alere Determine (99.8%). Positive predictive values at 95% CI were 100% for OraQuick ADVANCE and Uni-Gold and 98.4% for Alere Determine. Negative predictive values (at 95% CIs) were 99.1, 99.2 and 99.1 for OraQuick ADVANCE, Alere Determine, and Uni-Gold Ultra respectively. The results showed that these RDTs could only detect 12 out of every 13 HIV positive results. Conclusion: Third generation RDTs are not effective in detecting acute positive cases. Fourth generation Rapid Tests are required to capture the positive cases being missed out.


Author(s):  
Usha Adiga ◽  
Tirthal Rai

Objective: The objective of the study is to compare three techniques, routinely used rapid diagnostic tests (lateral flow immune chromatography) versus nucleic acid amplification test (NAT)  versus Paper-based microfluidics for DNA diagnostics of Malaria, in terms of their sensitivity and specificity as diagnostic tests in detecting malarial infection among febrile illnesses, suspected of malaria, as well as to compare their cost-effectiveness. Methodology: Three seventy febrile cases suspected of malaria with negative results with RDT will be screened by real-time PCR and DNA microfluidics techniques, sensitivity and specificity of these as screening tests will be compared. The number of extra positive cases detected by NAT gives us the yield. Cost-effectiveness analysis will be done by calculating the incremental cost-effectiveness ratio (ICER) and average cost-effectiveness ratio (ACER) for the tests. Statistical Analysis: Statistical analysis will be done using SPSS version 21. Sensitivity, specificity, Positive predictive values will be computed. Comparison of sensitivity and specificity of NAT, a paper microfluidic technique for DNA diagnostics and RDT will be carried out using McNemar’s test. Receiver operating curves will be generated separately to assess the utility of the NAT. Conclusion: The Implications of this study from the patient's perspective would mean early diagnosis which forms the tenet of control of the disease by increasing the yield. Early diagnosis at the community level would translate into the application of efficient prevention mechanisms to spread the infection. The cost-effectiveness analysis would provide a scientific basis for the adoption of the best test for the diagnosis, given the economic feasibility of the study.


2019 ◽  
Author(s):  
Eniyou C. Oriero ◽  
Adeola Y. Olukosi ◽  
Olabisi A. Oduwole ◽  
Abdoulaye Djimde ◽  
Umberto D’Alessandro ◽  
...  

AbstractWhile Plasmodium falciparum continues to be the main target for malaria elimination, other Plasmodium species persist in Africa. Their clinical diagnosis is uncommon while rapid diagnostic tests (RDTs), the most widely used malaria diagnostic tool, are only able to distinguish between P. falciparum and non-falciparum species, the latter as ‘pan-species’. Blood samples, both from clinical cases and communites, were collected in southern Nigeria (Lagos and Calabar) in 2017 (October-December) and 2018 (October–November), and analysed by several methods, namely microscopy, quantitative real-time PCR (qPCR), and peptide serology targeting candidate antigens (PmAMA1, PmLDH and PmCSP). The sensitivity of the diagnostic approaches for the dominant P. falciparum were comparable, detecting approx. 80% infection, but not so for non-falciparum species – 3% and 10% infection for P. malariae; 0% and 3% infection for P. ovale by microscopy and qPCR respectively, across communities. P. ovale prevalence was less than 5%. Infection rates for P. malariae varied between age groups, with the highest rates in individuals > 5 years. P. malariae specific seroprevalence rates fluctuated in those < 10 years but generally reached the peak around 20 years of age for all peptides. The heterogeneity and rates of these non-falciparum species calls for increased specific diagnosis and targeting by elimination strategies.


Author(s):  
Scott C. Litin ◽  
John B. Bundrick

Diagnostic tests are tools that either increase or decrease the likelihood of disease. The sensitivity, specificity, and predictive values of normal and abnormal test results can be calculated with even a limited amount of information. Some physicians prefer interpreting diagnostic test results by using the likelihood ratio. This ratio takes properties of a diagnostic test (sensitivity and specificity) and makes them more helpful in clinical decision making. It helps the clinician determine the probability of disease in a specific patient after a diagnostic test has been performed.


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