Anti-HIV I(0), II/p24 (Human) ELISA Kit

Transcription

1 Anti-HIV I(0), II/p24 (Human) ELISA Kit Catalog Number KA assays Version: 3.1 Intended for research use only

2 Table of Contents Introduction... 3 Intended Use... 3 Background... 3 Principle of the Assay... 4 General Information... 5 Materials Supplied... 5 Storage Instruction... 6 Materials Required but Not Supplied... 6 Precautions for Use... 6 Assay Protocol... 8 Reagent Preparation... 8 Sample Preparation... 8 Assay Procedure... 8 Data Analysis Calculation of Results Performance Characteristics Plate Layout KA / 13

3 Introduction Intended Use An enzyme-linked immunosorbent assay (ELISA) for the qualitative determination of HIV p24 antigen and/or antibodies to Human Immunodeficiency Virus (HIV) type 1 and/or type 2 in human serum or plasma. The kit contains reagents sufficient for 96 determinations and allows to analyze 45 unknown samples in duplicates. Background The human immunodeficiency viruses (HIV) type 1 and type 2 are proven to be the etiological agents of the acquired immunodeficiency syndrome (AIDS). The disease affects T-cell mediated immunity, resulting in severe lymphopenia and a reduced subpopulation of helper T-lymphocytes. Destruction of this T-lymphocyte population by the virus causes an immune deficiency, resulting in a reduced or deficient response to subsequent infections. Consequently, infections become more severe and may cause death. At present, there is no successful treatment for AIDS. The main routes of infection are sexual intercourse and blood transfusion. Infection with HIV is followed by an acute flu-like illness. This phase may remain unnoticed, and the relationship to HIV infection may not be clear in many cases. The acute phase is typically followed by an asymptomatic carrier state, which progresses to clinical AIDS in about 50% of infected individuals within 10 years after seroconversion. This long asymptomatic carrier state possesses a great danger as non-diagnosed carriers may disseminate infection through sexual transmission and even more important - blood donation. HIV can be present both in cellular and cell-free fractions of human blood. Therefore, all donations of blood or plasma should be tested. Since 1986, a number of commercial assays are available for blood screening for HIV. The ELISAs are the most common immunoassays utilized for detection of HIV antibodies and antigen. ELISAs have evolved from the first-generation (using viral lysate, detection of IgG antibody), to second-generation (recombinant antigens), third-generation (detection of IgM and IgG antibodies) and fourth-generation (antibody and antigen detection). The "window" period of HIV detection has been shortened to three weeks with the third-generation tests and to two weeks with the fourth-generation HIV tests. KA / 13

4 Principle of the Assay This test is based on two-site sandwich enzyme immunoassay principle. Microplate wells are coated with a mixture of recombinant HIV antigens (HIV-1, group M gp41, gp120, gp160; HIV-1, group 0 - gp41, HIV-2 gp36) and human monoclonal antibodies to HIV-1 p24 antigen. A sample is added to wells followed by a mixture of biotin-conjugated purified recombinant HIV antigens (gp41, gp36, gp120, gp160) and human monoclonal antibodies to p24, also biotinylated. If HIV antibodies and/or p24 antigen are present in a sample, they are bound both to a solid phase and to a relevant biotinylated reagent forming a complex which is visualized by streptavidin-peroxidase conjugate and chromogen (TMB substrate). Coloration intensity is directly relevant to levels of HIV antibodies and/or p24 antigen in the sample. KA / 13

5 General Information Materials Supplied List of component Component HIV1(0)/2, p24 EIA strips: Polystyrene microwells coated with recombinant HIV antigens; monoclonal Ab to p24. Negative Control (CONTROL-): Preselected human serum with preservative 0.01% Bronidox L, 0.01% 2-Methyl-4-isothiazolin-3-one-hydrochloride; no dyeation. Positive Control sera (CONTROL Ab+): Preselected human serum contained antibodies to HIV1(0)/2 preservative - 0,01% Bronidox L, 0.01% 2-Methyl-4-isothiazolin-3-one-hydrochloride; blue colour. Positive Control sera (CONTROL Ag+): Preselected human serum contained antibodies to p24, lyophilized, preservative - 0,01% Bronidox L, 0.01% 2-Methyl-4-isothiazolin-3-one-hydrochloride; red colour. Conjugate Concentrate (11x): aqueous solution of streptavidin coupled with horseradish peroxidase diluted on phosphate buffered saline with casein from bovine milk and detergent (Tween-20), contains 0.1% phenol as preservative; colourless. Conjugate Dilution Buffer: Aqueous Tris-buffered BSA solution, preservative 0.01% Bronidox L, 0.01% 2-Methyl-4-isothiazolin-3-one-hydrochloride; contains green dye. Tracer A Concentrate (11x): Phosphate buffered saline of recombinant HIV antigens; monoclonal Ab to p24, labeled with biotin; contains blue dye. Dilution buffer for Tracer A: Phosphate buffered solution with BSA, preservative 0.01% Bronidox L, 0.01% 2-Methyl-4-isothiazolin-3-one-hydrochloride; contains blue dye. Substrate: Solution containing tetramethyl benzidine (TMB). Washing Solution Concentrate 21x: Aqueous solution of sodium chloride, phosphate and detergent (Tween 20), contains proclin300 as a preservative. Stop Solution: 5.0% vol/vol solution of sulphuric acid. Plate sealing tape Amount 96 (8x12) wells 3 ml 1 ml 1 ml 1.2 ml 12 ml 0.4 ml 4 ml 14 ml 50 ml 14 ml 2 slides KA / 13

6 Storage Instruction Store the whole kit at 2 to 8 C upon receipt until the expiration date. After opening the pouch keep unused microtiter wells TIGHTLY SEALED BY ADHESIVE TAPE (INCLUDED) to minimize exposure to moisture. Component Stability of opened/diluted components HIV1(0)/2, p24 EIA strips until expiration date Negative Control (CONTROL-) 2 months Positive Control sera (CONTROL Ab+) 2 months Positive Control sera (CONTROL Ag+) 2 months Conjugate Concentrate (11x) Concentrate - until expiration date. Diluted - 1 day at 2-8 C Conjugate Dilution Buffer until expiration date Tracer A Concentrate (11x) until expiration date Dilution buffer for Tracer A until expiration date Substrate until expiration date Concentrate - until expiration date. Diluted washing solution Washing Solution Concentrate 21x - 1 month at 2-8 C or 5 days at RT Stop Solution until expiration date Plate sealing tape N/A Materials Required but Not Supplied Distilled or deionized water. Automatic or semiautomatic multichannel micropipettes, µl, is useful but not essential. Calibrated micropipettes with variable volume, volume range µl. Calibrated microplate photometer with 450\ nm wavelength and OD measuring range Microtiter plate shaker. Shaking should be medium to vigorous. Longitudinal shaking approximately 200 strokes/min, oscillations /min. Precautions for Use For professional use only. This kit is intended for research use only. INFECTION HAZARD: There is no available test methods that can absolutely assure that Hepatitis B and C viruses, HIV-1/2, or other infectious agents are not present in the reagents of this kit. All human products, including human samples, should be considered potentially infectious. Handling and disposal should be in accordance with the procedures defined by an appropriate national biohazard safety guidelines or regulations. KA / 13

7 Avoid contact with stop solution containing 5.0% H 2 SO 4. It may cause skin irritation and burns. Wear disposable latex gloves when handling specimens and reagents. Use disposable tips only - microbial contamination of reagents may give false results. Do not use the kit beyond the expiration date. All indicated volumes have to be performed according to the protocol. Optimal test results are only obtained when using calibrated pipettes and microplate readers. Do not smoke, eat, drink or apply cosmetics in areas where specimens or kit reagents are handled. Chemicals and prepared or used reagents have to be treated as hazardous waste according to the national biohazard safety guidelines or regulations. Do not mix reagents from different lots. Replace caps on reagents immediately. Do not swap caps. Do not pipette reagents by mouth. Specimens must not contain any AZIDE compounds they inhibit activity of peroxidase. The Material Safety Data Sheet for this product is available upon request directly from Abnova. The Material Safety Data Sheet fits the requirements of EU Guideline 91/155 EC. KA / 13

8 Assay Protocol Reagent Preparation All reagents (including unsealed microstrips) should be allowed to reach room temperature (18-25 C) before use. All reagents should be mixed by gentle inversion or vortexing prior to use. Avoid foam formation. It is recommended to spin down shortly the tubes with calibrators on low speed centrifuge. Prepare washing solution from the Washing solution concentrate 21x by 21 dilutions in distilled water. Sample Preparation This kit is intended for use with serum or plasma (ACD- or heparinized). Grossly hemolytic, lipemic, or turbid samples should be avoided. Do not heat the samples. The Specimens can be stored at 2-8 C within 7 days or they may be frozen at -20 C for several months. The plasma must be quickly thawed by warming for a few minutes in a water bath at 40 C (To avoid fibrin precipitation). Do not repeat more than 3 freeze/thaw cycles. If specimens are to be shipped, they must be packaged in accordance with the regulation in force regarding the transport of etiological agents. Assay Procedure Procedural Note: It is recommended that pipetting of all calibrators and samples should be completed within 3 minutes. 1. Put the desired number of microstrips into the frame; allocate 4 wells for the Negative control (CONTROL-) and positive control samples CONTROL Ab+ CONTROL Ag+ (one well each) and two wells for each unknown sample. DO NOT REMOVE ADHESIVE SEALING TAPE FROM UNUSED STRIPS. 2. Prepare working conjugate solution by dilution of conjugate concentrate (11X) 11 fold by conjugate dilution buffer. ATTENTION: working conjugate solution is unstable and should not be stored! Prepare the volume required for actual assay run. Prepare working biotin solution (Tracer A) by dilution of concentrate (Tracer A Concentrate (11x)) 11 fold by conjugate dilution buffer (Dilution buffer for Tracer A). ATTENTION: working conjugate solution is stable during expiry date of ready kit. 3. Pipet 70 µl of controls Negative Control (CONTROL-), CONTROL Ab+ CONTROL Ag+ and unknown samples into the wells. 4. Pipet 30 µl of working biotin solution (Tracer A) into each well. Cover the wells by plate adhesive tape. 5. Incubate 30 minutes at 37 C and continuous shaking at rpm. KA / 13

9 6. Prepare washing solution by 21x dilution of washing solution concentrate (21x) by distilled water. Minimal quantity of washing solution should be 250 µl per well. Wash strips 5 times. Allow a soak time of at least 30 seconds. 7. Dispense 100 µl of working conjugate solution into the wells. Cover the wells by plate adhesive tape. 8. Incubate 10 minutes at 37 C and continuous shaking at rpm 9. Wash the strips 7 times. Allow a soak time of at least 30 seconds Dispense 100 µl of Substrate solution into the wells. 11. Incubate 10 minutes at 37 C. 12. Dispense 100 µl of Stop solution into the wells. 13. Set photometer blank on air. Measure OD (optical density) at 450/ nm within 10 minutes of stopping the reaction (the strips must always be kept away from light before reading). KA / 13

10 Data Analysis Calculation of Results Quality Control It is recommended to use control samples according to state and federal regulations. The use of control samples is advised to assure the day to day validity of results. The test must be performed exactly as per the manufacturer s instructions for use. Moreover the user must strictly adhere to the rules of GLP (Good Laboratory Practice) or other applicable federal, state, and local standards and/or laws. This is especially relevant for the use of control reagents. It is important to always include, within the test procedure, a sufficient number of controls for validating the accuracy and precision of the test. The test results are valid only if all controls are within the specified ranges and if all other test parameters are also within the given assay specifications. For the assay to be valid, the following requirements should be met: 1. OD450/ for Positive Control (CONTROL Ab+) should be nlt 1.5 AU. OD450/ for Positive Control (CONTROL Ag+) should be nlt 0.3 AU. 2. OD450/ for Negative Control (CONTROL-) should not be more than 0.15 AU for all replicates. If any value lies outside this range, it should be discarded and not used for calculation of the mean OD450/ value for Negative Control (CONTROL-). Calculate the mean absorbance values (OD450/ ) for Negative Control (CONTROL-) using formula OD(Negative Control-1)+... +OD(Negative Control- n) ODmean(NegativeControl)= n n=number of replicates of Negative Control (CONTROL-) Calculate the cut-off value: Cut-off ODmean(Negative Control) Calculate Positivity Index (PI) for each sample: PI = meanod450/ (sample)/cut - off KA / 13

11 Expected Valued If PI value is greater than 1.1, the result is POSITIVE. If PI value is less than 0.9, the result is NEGATIVE. If PI value is between 0.9 and 1.1, the result is EQUIVOCAL. Such samples should be retested. If at least one of the replicates is positive, the sample is considered positive by this kit. Performance Characteristics Specificity Specificity has been evaluated by testing: 2000 random blood donors from 3 different sites. Specificity on random blood donors was 99.25% (1985 negative samples / 2000 tested samples) with 15 repeated reactive samples which were confirmed negative for HIV by Western Blot and HIV p24 Ag testing 120 individuals showing different status not linked to the HIV (pregnant women, rheumatoid factor, autoimmune (SLE), anti-mouse Ig or other viral or bacterial infections (Hepatitis B, C, rubella, Toxoplasmosis, CMV, HSV). Specificity was 99.17% (120/119) with 1 non specific and non significant reactions. The test also demonstrated 100% specificity on two proficiency panels approved in Russia (Medical Biological Union, Cat. IBS-8, INS-20. Analytical Sensitivity Confirmed HIV Ag positive samples The test demonstrated analytical sensitivity for p24 of not more than 5 pg/ml when checked on a panel with different p24 levels approved in Russia (Medical Biological Union, Cat. IBS-8, IPS-10-1). Sensitivity on HIV Ag positive samples: 56 samples were tested: 53 samples containing at least 15 pg/ml of HIV Ag were positive. Three samples p24 levels of 5, 6 and 4 pg/ml gave PI values of 1,1; 1,2 and 0,9, respectively. Confirmed HIV Ab positive samples The test also demonstrated a 100% sensitivity on two proficiency panels approved in Russia (Medical Biological Union, Cat. IBS-8, IBS-8-2). 560 HIV Ab positive samples (HIV-1 group M samples, HIV-1 group 0-10 samples, HIV-1 group N - 1 sample, HIV-2-60 samples) has been tested. This study was showing a sensitivity of 100% (560/560). 45 additional fresh Ab positive samples (within 1 day after blood collection) were tested and all were found positive. KA / 13

12 Precision The reproducibility of test has been determined, by the analysis of 10 samples: 1 negative sample, 3 HIV 1 positive samples, 3 HIV 2 positive samples and 3 Antigen positive. The intra assay reproducibility has been evaluated by testing these 10 samples 30 times in the same run. The inter assay reproducibility has been evaluated by testing these 10 samples in duplicates during 20 days on 2 independent runs each day. Intra-assay precision is shown below: Samples value, PI CV% Negative Low positive HIV-1 Medium positive High positive Low positive HIV-2 Medium positive High positive Low positive HIV Ag Medium positive High positive Inter-assay precision is shown below: Samples value, PI CV% Negative Low positive HIV-1 Medium positive 5.3 5,7 High positive Low positive HIV-2 Medium positive High positive Low positive HIV Ag Medium positive High positive KA / 13

13 Plate Layout A B C D E F G H KA / 13