Assessment of Sensitivity and Specifity Immunochromatograophy Test And ELISA for detecting Human Immunodeficiency Virus Antibodies among Screening Patients in Khartoum State

Abstract 

Human Immunodeficiency Virus ( HIV) is global and serious problem , with increase in mortality and morbidity worldwide. This was prospective , descriptive and cross sectional study aimed to assess the level of HIV Ab using the ICT and ELISA for detecting Ab and Ag (p24) .It was conducted among Screening patient in Khartoum state (National Public Health Laboratory) from 1 April to 30 June (2015) on a total of eighty nine (n=89)to compare the sensitivity and specificity of immunochromatographic test and ELISA in detecting HIV Ab .All subject examined in this study from both sex male and females . 14 (15.7 %) of screening patients were positive for HIV Ab by ICT, Where it decrease to 13(14.6%) by ELISA procedure run on the same serum sample .there was one false negative result when tested by ICT . total of previous blood transfusion .only 7 % who had positive for HIV Ab when tested by ELISA . The highest prevalence was on the age group (21- 40) years and low rate ( 61 – 80). The result obtained show that the ICT technique has 100% ,98.6 % respectively sensitivity and specificity for detection of HIV Ab .While ELISA revealed 100% for both sensitivity and specificity .Results showed that the ICT used in this study for HIV Ab was less specific compare to ELISA. Among married screening patients 55/89 (61.8 %) higher than single 34/89(38.2%) positive cases were 7/55(7.9%) among married and 6/34(6.7%) among single .were examined by ELISA . In those who has previous surgical operation and multi transfusion only 7 % who had positive for HIV when tested by ELISA .

Table of Content

Dedication II

Acknowledgment III

Abstract(English) IV

Abstract (Arabic) V-VI

Contents VII

List of tables XI

List of figures XII

List of abbreviations XIII-IX

Chapter one:(Introduction)

1. Introduction 1

1.1 Rationale 3

1.2 Objectives 3

1.2.1 General objectives 3

1.2.2. Specific objectives 3

Chapter Two: Literature Review

2.1 HIV 4

2.2 History Of HIV 4

2.3 Epidemiology 5

2.3.1 Epidemiology in Sudan 6

2.4 HIV Structure 6

2.4.1 NON infectious Particle 8

2.4.2 HIV genome 8

2.4.3. HIV Antigen (Ag )and Antibody ( Ab ) 9

2.5 Classification 10

2.6 Stability 10

2.7 Transmission 11

2.8 Replication Cycle 12

2.9 Pathogenesis& immune responce 14

2.10 Clinical finding and stages 16

2.10.1 Acute phase 16

2.10.2 Chronic Phase 16

2.10.3 AIDs phase 17

2.11 Laboratory Diagnosis of HIV 18

2.11.1 Screening test 19

2.11.2 Supplemental or Confirmatory 19

2.11.3 Other test 19

2.11.4 Alternative to classical test 19

2.12 Ag Detection 19

2.13 Ab detection 20

2.13.1 Immunochromatography test (ICT) 21

2.13.2 Enzyme linked Immuno Sorbent Assay )(ELISA) 21

2.14 Confirmatory Western blot Technique (WB) 23

2.15 (Immuno flurosent Assay )IFA 24

2.16 Polymerase Chain Reaction (PCR) 24

2.17 HIV-RNA 24

Chapter Three: Material &Methods

3 Material &Methods 25

3.1 Study Design 25

3.2 Study area 25

3.3 Study Population 25

3.4 Study duration 25

3.5 Ethical Consideration 25

3.6 Sample size 25

3.7 Data collection 26

3.8 Sample Collection 26

3.9 Laboratory methods 26

3.9.1 Immunochromatographic Test (ICT) 26

3.9.1.1 Principle Of the Test 26

3.9.1.2 Storage and stability 27

3.9.1.3 Procedure of the test interpretation of the result 27

3.9.1.4 Interpretation of the test Result 27

3.9.2 Enzyme Linked Immune Sorbent Assay (ELISA) 28

3.9.2.1 Principle Of the Test 28

3.9.2.2 Storage and stability 29

3.9.2.3 Procedure of the test interpretation of the result 29

3.9.2.4 Reading of the test Result 30

3.9.2.5 Calculation Of the Cut of value 31

3.9.2.6 Quality control Ranges 31

3.9.2.7 Interpretation of the test Result 31

3.9.2.8 Performance characteristic 31

3.9.2.8.1 Specificity 31

3.9.2.8.2 Sensitivity 32

3.9.2.8.3 Positive Predictive Value 32

3.9.2.8.4 Negative Predictive Value 32

3.10 Data analysis 32

Chapter Four :Results

4 Results 33

4.1 Distribution of Screening Patients according gender 33

4.2 Distribution of Screening Patients according to marital status 34

4.3 Distribution of Screening Patients according to Age 35

4.3 The Effect of previous Blood Transfusion On HIV Infection 36

4.4 The Effect of previous Surgical operation On HIV Infection 36

4.6 ICT and ELISA results 37

4.7 Sensitivity &Specificity of ICT and ELISA test 38

4.8 Predictive Value Of ICT and ELISA 39

Chapter Five : Discussion

5 Discussion 40

5.1 Conclusion 42

5.2 Recommendations 42

References 43

Appendix