Reduce the Window Period
 

Reduce the Window Period

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The study was done to detect simultaneously the antigen and the antibodies in HIV patients attending the STD-OP of a tertiary care centre. A total of 114 patients were screened for HIV status. The ...

The study was done to detect simultaneously the antigen and the antibodies in HIV patients attending the STD-OP of a tertiary care centre. A total of 114 patients were screened for HIV status. The regular protocol by NACO has detected only one case out 114 patients, whereas simultaneous detection of Ag and Ab by ELISA method has detected 2 more patients. This study highlights the necessity for using the newer generation kits in detecting new cases at the earliest and to reduce the window period.

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Reduce the Window Period Reduce the Window Period Document Transcript

  • Reduce the Window Period
  • Brief Report Reduce the window period Subbian Arunkumar a, *, N. Thilakavathi b , Adisesh Mangala b , Rajagopal Vasanthi b a Department of STD, Chengalpattu Medical College, Chengalpattu, Tamilnadu, India a Institute of Venereology, Madras Medical College, Chennai, Tamil Nadu, India a r t i c l e i n f o Article history: Received 7 March 2012 Accepted 8 May 2013 Available online 7 June 2013 Keywords: HRG e High Risk Groups HIV e human immunodeficiency virus Fourth generation HIV kit a b s t r a c t The study was done to detect simultaneously the antigen and the antibodies in HIV pa- tients attending the STD-OP of a tertiary care centre. A total of 114 patients were screened for HIV status. The regular protocol by NACO has detected only one case out 114 patients, whereas simultaneous detection of Ag and Ab by ELISA method has detected 2 more pa- tients. This study highlights the necessity for using the newer generation kits in detecting new cases at the earliest and to reduce the window period. Copyright ª 2013, Indraprastha Medical Corporation Ltd. All rights reserved. 1. Introduction Worldwide HIV infection is estimated in more than 33 million people and there are an estimated 2 million deaths per year and there are about 2.7 million new HIV infections per year. Approximately one-fourth of all HIV infections in adults remain undiagnosed and that close to 60% of AIDS diagnosed individuals discovered their seropositives at the diagnosis of AIDS. Late diagnosis of HIV infection is associated with increased mortality and morbidity and increased cost to healthcare services.1 The diagnosis of primary infection usually is achieved with standard antibody serologic tests. The inclusion of P24 antigen assay can help to detect HIV infection before the development of antibodies. Advanced 4th generation assays can detect simultaneously the P24 antigen and antibodies of HIV in serum. Usually we do the tests to detect antibodies e the window period is 6e12 weeks. Here we are trying to reduce the window period by performing the 4th Generation ELISA for HIV in the High Risk Group (HRG) individuals attending the Institute of Venereology (IOV). 2. Objectives 1) To decrease the window period in HRG patients attending the IOV by using Advanced 4th Generation ELISA for HIV. 3. Materials and methods HRG individuals attending the IOV with recent sexual expo- sure were included into the study after getting the consent and pre-test counselling. Blood sample was collected. All the samples are tested for HIV both by the conventional method e NACO protocol (Strategies III e 2007)2 and by 4th Generation ELISA Kits (RFCL) using automated ELISA reader and washer. The period of study was between 1st September to 5th September 2009. 4. Results Total number of patients tested 114: all are HRG patients. Male e 74, Female e 40. * Corresponding author. Tel.: þ91 9884166648. E-mail address: arunssshc@gmail.com (S. Arunkumar). Available online at www.sciencedirect.com journal homepage: www.elsevier.com/locate/apme a p o l l o m e d i c i n e 1 0 ( 2 0 1 3 ) 1 5 2 e1 5 4 0976-0016/$ e see front matter Copyright ª 2013, Indraprastha Medical Corporation Ltd. All rights reserved. http://dx.doi.org/10.1016/j.apme.2013.05.006
  • Results of the routine ELISA test Results of the 4th Generation ELISA 5. Discussion Antibody is detected in a majority of individuals within 6e12 weeks after infection with the present tests, but antibody levels can be detected within 3e4 weeks after infection when the newer third generation sandwich assays are used.3 This window period can be further shortened to about 2 weeks using p24 antigen assays or to 1 week further with imple- mentation of nucleic acid detection assays.4 The detection of early infection has been shown to be beneficial for the prompt initiation of appropriate antire- troviral therapy in a clinically relevant time frame and an evaluation reported that the time needed to diagnose acute infection was shortened to approximately 2 weeks.5 Use of nucleic acid testing and viral culture are highly sensitive and specific methods to identify infection, respectively, these procedures are time consuming, laborious and expensive.6 HIV p24 antigenemia occurs early after infection; however, when the antibodies become detectable, antigen is usually not demonstrable, most likely because of antigen e antibody complexes in the blood, thereby necessitating the test for HIV antibody as well.7 The benefits of testing for both the antibody and antigen are justifiable due to the need to identify individuals with both established and early HIV infections not only within the blood donor population but also in general population. Early detection of infection via antigen testing promotes the prompt referral of infected individuals for the initiation of treatment, counselling, and prevention interventions to reduce the risk of transmission.7 In our study we were able to detect more patients by using the 4th generation ELISA test for HIV. Consequently, the window period between infection and detection of infection may be reduced to 3 weeks if a comprehensive testing approach is used.7 In addition to increased sensitivity and specificity with the incorporation of recombinant proteins and synthetic peptide antigens, these 4th Generation ELISA offers several advantages over other types of assays in that it is inexpensive, relatively simple, reproduceable, suitable for testing sizeable number of sam- ples, and easily adopted to automated platforms. By implementing antigen screening of blood, HIV in- fections are prevented and lowering the risk of transmission through blood transfusion in USA,8,9 organ transplantation, mother to child transmission. Establishing the diagnosis in discordant couples and medico legal cases. A comparison of four of the commercial fourth genera- tion assays versus four third generation antibody ELISAs using seroconversion panels reported that all four of the fourth generation assays detected infection in fewer days than did all the third generation ELISAs, thus indicating that these assays show promise in reducing the window period by detecting early infection.10 The ability of this test to enhance the diagnosis of those with acute HIV infection will provide additional benefits in HIV prevention pro- grammes and ultimately contribute to a reduction in the spread of HIV. Rapid 4th Generation tests are superior to 3rd generation tests in detecting HIV antibody responses.11 6. Conclusion Use of Advanced 4th Generation ELISA identified 2 patients more while they are under seroconversion phase. Hence we are in need of these advanced 4th generations ELISA kits to detect the early HIV infection thereby preventing the trans- mission of new infection. Prevention of new infection by 50% is the goal by 2010, in the NACP 3, which can be achieved by using this principle. Conflicts of interest All authors have none to declare. r e f e r e n c e s 1. Butto Stefano, Raimonda Mariangela, Fanales- Belasio Emanuele, Suligoi Barbara. Suggested Strategies for the Laboratory Diagnosis of HIV Infection in Italy; 2010. 2. Laboratory Manual for Technicians; 2007. http://www. nacoonline.org. 3. Constantine NT, van der Groen G, Belsey E, Heymann D, Tamashiro H. Sensitivity of HIV antibody assays as determined by seroconversion panels. AIDS. 1994;8: 1715e1720. (Medline). 4. Feinberg MB. Changing the natural history of HIV disease. Lancet. 1996;348:239e246. (Cross Ref) (Medline). 5. Martinez-Martinez P, Martin del Barrio E, De Benito J, Landinez R. New lineal immunoenzymatic assay for simultaneous detection of p24 antigen and HIV antibodies. Eur J Clin Microbiol Infect Dis. 1999;18:591e594. (Medline). 6. Constantine NT. HIV antibody testing. In: Cohen PT, Sande MA, Volberding PA, eds. The AIDS Knowledge Base. 3rd ed. Philadelphia, Pa: Lippincott-Williams & Wilkins; 1999: 105e112. 7. Constantine NT. Tests to detect HIV antigen. In: Cohen PT, Sande MA, Volberding PA, eds. The AIDS Knowledge Base. 3rd ed. Philadelphia, Pa: Lippincott-Williams & Wilkins; 1999: 113e118. Positive Negative In determinant Total 1 113 0 114 Positive Negative In determinant Total 3 110 1 114 a p o l l o m e d i c i n e 1 0 ( 2 0 1 3 ) 1 5 2 e1 5 4 153
  • 8. Dixon NR. Global goals of today’s blood banks. Adv Admin Lab. 1996;5:20e30. 9. Lackritz EM, Satten GA, Aberle-Grasse J, Dodd RY, Raimondi VP, Janssen RS. Estimated risk of transmission of the human immunodeficiency virus by screened blood in the United States. N Engl J Med. 1995;333:1721e1725. (Abstract/ Free Full Text). 10. Courouce AM, The Retrovirus Work Group at the S.F.T.S. Combined screening tests for anti-HIV antibodies and p24 antigen. Gaz Transfus. 1999;155:4e18. 11. Chetty Vani, Moodley Dhayendre, Chuturgoon Anil. Evaluation of a 4th generation rapid HIV test for earlier and reliable detection of HIV infection in pregnancy. J Clin Virol. June 2012;54(2):180e184. a p o l l o m e d i c i n e 1 0 ( 2 0 1 3 ) 1 5 2 e1 5 4154
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