Dengue is an important public health problem worldwide. Dengue virus infection can produce self-limiting illness to fatal life threatening complications like dengue hemorrhagic fever [DHF] and dengue shock syndrome [DSS]. Dengue specific NS1 antigen, IgM and IgG antibody detection can be used for early diagnosis which is essential for effective management of cases to reduce the mortality and morbidity. The only non-dengue parameter which helps in predicting complications is platelet count. Therefore we tried to evaluate the association of platelet count against NS1 and lgG/lgM in dengue infections. The study includes detection of dengue NS1antigen by ELISA in patients having 1 to 5 days fever, detection of dengue NS1 antigen and IgM antibody by ELISA in patients having fever of five to nine days and only detection of IgM antibody by ElISA in patients having fever of more than 9 days. Platelet count of the positive patients for dengue NS1 antigen and IgM antibody by ELISA were seen. The present study was done in department of Microbiology Osmania General Hospital, Hyderabad during year March 2015 to October 2015. 426 serum samples from patients with a suspecting of dengue infection were collected. These patients were divided into three groups according to days of fever Group I - Patients having 1 to 5 days fever were tested for NS1 antigen ELISA. Out of 132 tested 35(26.5%) patients were positive for dengue NS1 antigen. Group II: Total patients having fever more than 5 days to 9 days were 106. Out of 106 samples, 44 (41.5%) were positive either for NS1 ag or IgM ab or both. A total of 16 (15%) samples were positive for NS1 Ag and 33 (35%) were positive for IgM ab including t significantly increased the detection rate to 41.5% .those that were positive by both. Both the assays, performed together on a single serum sample. GROUP III: 188 patients were having fever of more than 9 days. These were tested for only Dengue IgM ELISA. 68(36.1%) patients were showing positive for dengue IgM by ELISA. Platelet counts of patients positive for dengue NS1 antigen and IgM were noted. Platelet count < 1 lac /cumm is considered as Thrombocytopaenia, which was seen in 87% of seropositive cases. Mild TCP observed in 29.6 % of seropositives. TCP was seen in 30.8% of seronegative cases. More no. of Seronegatives (24.4 %) was observed between 61,000-80,000/cumm Platelet count. TCP with seropositivity (87.7%) and seronegativity (30.8%). Mild TCP noticed in highest no.of patients 29.1, followed by Moderate in 16.4% and severe in only 4.6% of cases. Platelet count <1 lac/cumm was associated significantly when both serological markers were detected (95%) than with individual markers NS1 (91%) and IgM (80.7%). In the present study, 91.4% TCP was noticed in NS1 seropositive. TCP was noticed in 95.4% when simultaneous detection of NS1& Ig M done. Decrease in Platelet count seen in 80.8 % of Ig M seropositives. The study concluded that combination of dengue NS1 antigen and IgM ELISA on single sample can improve the diagnosis of dengue without the requirement of paired sera. Correlations of positive samples with platelet counts were noted. Apart from dengue specific marker parameter platelet count is the only accessory laboratory test available that can support the diagnosis for dengue. Association of thrombocytopenia in dengue parameter positive cases was highly significant when compared to thrombocytopenia in dengue parameter negative cases.
