Rdt

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  • 1. RAPID DIAGNOSTIC TESTS FOR MALARIA Pospective study Dr. PRABHASH KUMAR Deptt. Of Pediatrics, J.L.N.H R.C.,Bhilai Steel Plant. www.dnbpediatrics.com
  • 2. AIMS AND OBJECTIVES  To Evaluate the usefulness of the rapid diagnostic test(RDTs) for diagnosis of Malaria.  To compare RDTs with microscopic examination for the diagnosis of Malaria. www.dnbpediatrics.com
  • 3. INTRODUCTION  Malaria is the most common serious parasitic disease of human beings, killing one person every 12 seconds.The majority of these deaths being seen in the pediatric age group and pregnant women  Microscopy - the “Gold standard” for diagnosis of malaria, but requires up to 60 minutes for reporting of result.  Poor result particularly at low levels of parasitemia and requires expertise for interpretation. www.dnbpediatrics.com
  • 4. INTRODUCTION cont…. The Immunochromatographic test(RDTs) for malaria - introduced in the early 1990s RDTs tests capture the parasite antigens from the peripheral blood using either monoclonal or polyclonal antibodies against the parasite antigen targets.  Currently, RDTs tests can target :  the histidine-rich protein 2 of P. falciparum(PfHRP2)  the parasite specific lactate dehydrogenase(pLDH). www.dnbpediatrics.com
  • 5. INTRODUCTION cont….  If both microscopy and rapid diagnostic tests are used concurrently, they contribute to each other. In remote areas where trained staffs are not available to do microscopy and in severe malaria e.g. cerebral malaria, where we need urgent diagnosis, RDTs are very useful.  So, the present study aims to evaluate the usefulness of RDTs as compare to microscopy for detection of malarial parasite. www.dnbpediatrics.com
  • 6. MATERIAL AND METHOD  STUDY AREA : Department of Pediatrics, JLN Hospital & Research Centre, Bhilai, CG.  STUDY POPULATION: All patients in the age group upto 14 years admitted to the paediatric wards and PICU on suspicion of malaria.  SAMPLE SIZE : Study group consisted of 43 cases diagnosed as malaria based on either on microscopy and / or +ve RDTs test. www.dnbpediatrics.com
  • 7. MATERIALS AND METHODS STUDY PERIOD :  From Aug.’2008 to Feb.’2010. STUDY DESIGN:  Prospective and Comparative study. STATISTICAL ANALYSIS:  Chi square test (χ2 ) www.dnbpediatrics.com
  • 8. MATERIALS AND METHODS  SELECTION OF CASES  INCLUSION CRITERIA:  Patients with any of the following clinical features were included in the study group :  Acute febrile illness with or without chills or rigor.  Acute febrile illness with  altered sensorium.  jaundice or pallor.  oliguria.  seizures. splenomegaly or hepatomegaly  Atypical presentations with suspected malaria. www.dnbpediatrics.com
  • 9. RAPID DIAGNOSIS OF MALARIA BY RDTs TEST KIT www.dnbpediatrics.com
  • 10. INTERPRETATION OF THE RDTs TEST o FALSE POSITIVE :  gametocytemia, with no persistent viable asexual- stage parasitemia.  persistence of antigens due to sequestration.  delayed clearance of circulating antigen (free or in antigen-antibody complexes).  cross reaction with non-falciparum malaria or rheumatoid factor. www.dnbpediatrics.com
  • 11. INTERPRETATION OF THE RDTs TEST  FALSE NEGATIVITY:  genetic heterogeneity of PfHRP2 expression.  deletion of HRP-2 gene.  presence of blocking antibodies for PfHRP2 antigen or immune-complex formation.  prozone phenomenon at high antigenemia. www.dnbpediatrics.com
  • 12. OBSERVATION  The observations made during the course of study are presented here : www.dnbpediatrics.com
  • 13. OBSERVATION Distribution of Plasmodium species in Malaria cases (In species diagnosed cases) (n=43) P.falciparum P.vivax Mixed www.dnbpediatrics.com • 38cases • 88.37% • 3 cases • 6.98% • 2 cases • 4.65%
  • 14. , Distribution of Plasmodium species in Malaria cases www.dnbpediatrics.com
  • 15. OBSERVATION RDTs in comparison to Microscopy (Plasmodium falciparum malaria) RDTs Test Microscopy Total +ve -ve Positive 28 11 39 Negative 1 3 4 29 14 43 Total 11 cases of falciparum malaria missed by microscopy were diagnosed by RDTs. But RDTs missed 1 case diagnosed by microscopy. www.dnbpediatrics.com
  • 16. OBSERVATION When microscopy is considered as “gold standard ”, the values for RDTs are: Sensitivity P.falciparum Specificity of RDTs P.falciparum 96.55% 21.43% PPV of RDTs P.falciparum NPV of RDTs P.falciparum 71.79% 75% of RDTs www.dnbpediatrics.com
  • 17. OBSERVATION RDTs in comparison to Microscopy (Plasmodium vivax malaria) RDTs TEST MICROSCOPY TOTAL +VE -VE Positive 2 0 2 Negative 3 38 41 Total 5 38 43 No any case of vivax malaria missed by microscopy and all were diagnosed by RDTs. But RDTs missed 3 cases diagnosed by microscopy. www.dnbpediatrics.com
  • 18. OBSERVATION When microscopy is considered as “gold standard ”, the values for RDTs are : Sensitivity of RDTs Specificity of RDTs 40% 100% P.Vivax malaria PPV of RDTs 100% www.dnbpediatrics.com NPVof RDTs 92.68%
  • 19. OBSERVATION Efficacy of RDTs Test (n=43) RDTs Not Diagnosed RDTs Diagnosed 41 2 Microscopy diagnosed Microscopy Not Diagnosed 34 9 CHI -SQUARE χ2= 5.12 P < 0.05 www.dnbpediatrics.com
  • 20. OBSERVATION RDTs 50 40 Microscopy 41 34 30 20 2 10 9 0 Diagnosed www.dnbpediatrics.com Not Diagnosed
  • 21. RESULT  Over all Result from the Obervations found in the present study :  For P.falciparum Malaria : False +ve 11 cases RDTs Diag. 39 cases Microscopy 29 cases False –ve 1 case www.dnbpediatrics.com For P.falciparum Malaria
  • 22. RESULT  For P.vivax Malaria : False +ve 0 case RDTs Diag. 2 cases Microscopy 5 cases False –ve 3 case www.dnbpediatrics.com For P.vivax Malaria
  • 23. RESULT  For Total No. of cases, ie; n =43 Mixed 2 cases P.Falciparum P.Vivax 38 cases 3 cases Total cases 43 cases Of study group www.dnbpediatrics.com
  • 24. CONCLUSION Efficacy of RDTs test 43 • Total Malarial cases selected for present study 41 • Diagnosed by RDTs Test 34 • Diagnosed by Microscopy www.dnbpediatrics.com
  • 25. CONCLUSION Distribution of Plasmodium Species in Malaria cases (diagnosed cases , n = 43) 38(88.37%) •P. falciparum 3(6.98%) •P. vivax 2(4.65%) •Mixed www.dnbpediatrics.com
  • 26. CONCLUSION  RDTs is an effective, simple, sensitive, specific and rapid (within 20 minutes) test for diagnosing malaria especially in falciparum malaria where immediate diagnosis and management is required.  Thus, availability of a simple, rapid and accurate test could greatly aid in the early diagnosis of malaria including in remote areas.  RDTs is significantly better than microscopy in diagnosis of malaria.  The best approach for diagnosis of malaria would be the combination of RDTs and microscopy. www.dnbpediatrics.com
  • 27. RAPID DIAGNOSIS OF MALARIA ABSTRACT……  Malaria is a resurging problem all over the country and rapid diagnosis is mandatory to decrease the morbidity and mortality.  Sensitivity & Specificity of RDTs evaluated and compared with test with peripheral blood smear examination which is the “gold standard ”.  RDTs diagnosed 41 cases out of 43 cases ultimately diagnosed to have malaria and Microscopy diagnosed 34 cases. Out of these 43 cases diagnosed , 38 cases was of P.falciparum, 2 cases was of P.vivax and 2 cases was of mixed of both( which were ultimately taken as cases of P.falciparum as RDTs. www.dnbpediatrics.com
  • 28. THANKS…… www.dnbpediatrics.com
  • 29. Immunochromatographic dipstick Assay for Malaria www.dnbpediatrics.com
  • 30. BAND INTERPRETATION OF RDTs TEST The PfHRP2 test strips have 2 lines, I for the control and the other for the PfHRP2 antigen  The pLDH test strips have 3 lines, 1 for control, and the other 2 for P. falciparum (PfHRP2 or pLDH specific for P. falciparum) and non-falciparum antigens (pan specific pLDH), respectively.  Change of color on the control line is necessary to validate the test and its non-appearance, with or without color changes on the test lines, invalidates the test.  With color change only on the control line and without color change on the other lines, the test is interpreted as negative www.dnbpediatrics.com
  • 31. RESULT  Antigen detection test for P.falciparum & P.vivax by Immunochromatographic dipstick assay is useful for Rapid diagnosis of malaria, as in the present study. www.dnbpediatrics.com