Sachin Kale, MD (Pathology). Malaria Diagnosis

Approaches  Clinical  Microsopy  RDTs

Microscopy

 Sensitive  5 – 10 parasites/ul  100 parasites/ul (in field conditions.)  Informative  Species  Inexpensive

Microscopy  Permanent record  Quality control  Disadvantages  Labour intensive  Exacting

 Nikon Coolpix 3700  Vision 2000  Camera mode: Manual  White Balance: Auto  Size: 1024x780 Conflict of Interest Statement: No association with any of above brands. Photomicrography

Vivax Falciparum

Vivax Falciparum

Rapid Diagnstic Tests

Antigens  HRP-2  p-LDH

Suspected cases RDT/PS +ve-ve P.f Severe T/t Uncomplicated T/t High Suspicion T/t, exclude Other diseases Other diseases, Review/refer Low Susp

Species-specific PCR diagnosis of malaria  5 parasites or less/ul  Species identified

Other Approaches  Quantitative buffy coat  Fluorescence Microscopy  Sensitivity: 41 to 93 % (0.002% parasitemia)  Specificity: 93%(P.f)  No species identification

Ancillary Tests  Hb, PCV  Blood glucose  WBC, Platelet Count  Coagulation tests; FDPs, Fibrinogen  Urine for free Hb  Blood Urea/ Creatinine  Urine Protein  G6PD

Poor Prognosis  Heavy parasitemia >5% RBC  Presence Malarial pigment, schizonts and mature trophs  WBC > 12,000/cmm  Creatinine: > 2.9 mg/dl  BUN: 128 mg/dl  PCV: < 20%, Hb: < 7.0 gm/dl  Blood glucose: < 40  Riased transaminases

 Iqbal et al. (J. Clin. Microbiol. 39:3644–3646. ) looked at pLDH detection compared to microscopy and PCR in 550 immigrants from malaria-endemic areas who were entering Kuwait, where malaria is not endemic. They concluded that for parasite levels of >100 parasites/µl, the sensitivity obtained for OptiMAL was 97%. However, because half of the samples with <50 parasites/µl detected by microscopy were not detected, the authors recommended that the test should be used with great caution and should not replace conventional microscopy in the diagnosis of malaria.

Diagnostic and Prognostic Utility of Rapid Strip (Optimal and Paracheck) Versus Conventional Smear Microscopy in Adult Patients of Acute, Uncomplicated P. falciparum Malaria in Mumbai, India NJ Gogtay*, SS Dalvi**, D Rajgor***, AR Chogle#, DR Karnad+++, M Ramdas+, U Aigal##, NA Kshirsagar++

 Thrombocytopenia in malaria  Patel U, Gandhi G, Friedman S, Niranjan S.  The study found the sensitivity of platelet count for diagnosing malaria was 100%, and the specificity was 70%.  The negative predictive value was 100% and the positive predictive valve was 86%.  J Natl Med Assoc Sep;96(9):1212-4

Clinical Microbiology Reviews, January 2002, p , Vol. 15, No. 1

References  Treatment of Malria  The use of Malaria Rapid Diagnstic Tests. WHO, Roll Back Malaria  REPORT OF A JOINT WHO/USAID INFORMAL CONSULTATION 25–27 OCTOBER 1999 New Perspectives Malaria Diagnosis   Clinical Microbiology Reviews, January 2002, p , Vol. 15, No. 1

Thank You ! Visit us at – Phone: and