| Introduction |
| HIV
(human Immunodeficiency Virus) is recognized as the etiologic agent of
Acquired Immune deficiency Syndrome (aids). The virus is transmitted by
sexual contact, exposure to infected blood, certain body fluids or tissues,
and from mother to fetus or child during the perinatal period. The clinical
diagnostic issues related to HIV are the detection of HIV 1 & 2 antibodies
in human plasma, serum or whole blood by immunoassay. Among the existing
immunological methods, the ELISA format and immunochromatographic format
(rapid) to detect antibody of HIV are most commonly used. Synthetic peptides
and recombinant antigens defining the antigenic determinants of HIV proteins
find wide applications in ELISA procedure for the detection of anti- HIV
antibodies in serum. It has been observed that the use of recombinant
antigen for both detector and capture materials markedly increases both
the sensitivity and the specificity when compared to another rapid kit
based on only synthetic peptides. Researchers have constructed HIV 1&2
genes for the expression of recombinant antigens in bacterium systems
such as E.coli and focused on HIV1 & 2 proteins, which are definitely
immunogenic. The major immunoreactive antigens of these proteins have
been reported to have HIV-1 gp41, p24 and HIV-2 gp36 based on western
blot analysis. |
| Aids test Rapid HIV Card Test 1-2.O |
| It
is an immunochromatographic (rapid) test for the qualitative detection
of antibodies of all isotopes (lgG, IgM, IgA) specific to HIV-1 including
subtype O and HIV-2 in human serum, plasma or whole blood. |
 |
|
| Aids
test Rapid HIC Card Test 1-2.O |
| It
contains a membrane strip, which is pre- coated with recombinant HIV1
capture antigens (gp41 including subtype O and p24) on test band “1”
region and with recombinant HIV2 capture antigen (gp36) on test band “2”
region, respectively on the Test Device. The recombinant HIV1 & 2
antigens (gp41, p24, gp36)- colloidal gold conjugate and serum sample
moves along the membrane chromatographically to the test region and forms
a visible line (test line) as the antigen- antibody- antigen gold particle
complex. The Test Device had markings “C”, “2”
and “1” on it at the corresponding positions of “Control
Line”, “HIV-2” and “HIV-1” on the membrane.
No line will be visible in the result window before applying any sample.
The control line is used for procedural control. Control line should always
appear if the test procedure is performed properly and the test reagents
of control line are working. |
| Materials
Provided |
| Aids test rapid HIV 1-2.O-card test. |
| Dropper pre- filled with assay developer. |
| Disposable alcohol swab. |
| Disposable lancet. |
| Product insert. |
|
|
|
Precautions |
| Aids
test Rapid HIV Card Test 1-2.O Test device should be stored at 4-30*C.
The Test Device is sensitive to humidity and heat. Allow the Test Device
to come to room temperature before opening the foil pouch. Perform the
test immediately after removing the Test Device from the foil pouch. Do
not use it beyond the expiration. |
| Specimen collection & storage |
 |
Whole
Blood: Collect the whole blood using suitable anticoagulant.
Blood may also be drawn directly by finger prick. |
|
Serum
or Plasma: Centrifuge whole blood collected with or without
an anticoagulant to get plasma or serum. |
|
If
serum or plasma specimens are not immediately tested, they should
be refrigerated at 2*-8*C. For storage periods greater than three
days, freezing is recommended. They should be bought to room temperature
prior to use. |
|
Serum
or plasma specimens containing precipitate may yield inconsistent
test results. Such specimens must ALWAYS be centrifuged prior to assaying. |
|
Whole
body specimen may be used for testing immediately or may be stored
at 2*- 8*C for up to 3 days. |
|
| Warnings |
| For
in vitro diagnostic use only. |
| Do not eat or smoke while handling specimens. |
| Wear
protective gloves while handling specimens. Wash hands thoroughly
afterwards. |
| Avoid splashing or aerosol formation. |
| Clean up spills thoroughly using an appropriate disinfectant. |
| Decontaminate
and dispose of all specimens, reaction kits and potentially contaminated
materials, as if they were infectious waste, in a biohazardous waste
container. |
| Do not use the test kit if the pouch is damaged or the seal is broken. |
|
| Procedure |
| Remove
the Test Device and the dropper from the foil pouch and place it on
a flat, dry surface. |
| Slowly add 10 ul (one drop) of serum/ plasma or 20 ul ( two drops)
of whole blood to the sample well (S) and then add 35 ul (one drop)
of the Assay Diluent. |
| As the test begins to work, you will see purple color move across
the Result Window in the center of the Test Drive. |
| Interpret test results at 5- 15 minutes. |
| Do not interpret after 15 minutes. |
|
| Caution |
| The above interpreting time is based on reading the test results at room
temperature of 15 – 30* C. If the room temperature is significantly
lower than 15*C, then the interpreting time should be increased appropriately. |
| Interpretation of the test |
| A
color band will appear at section ‘C’ of the Result Window
to show that the test is working properly. This band is the Control
Band. |
| The test results appear in the section “T” of the Result
Window. The test band appears at “1” and/or “2”
for HIV-1 and/or HIV-2. |
|
| Negative
Result |
| The
presence of only one band within the result window at the control line
“C” region indicates a negative result |
 |
|
| Positive
Result |
| If two color bands, one control © and the other for HIV-1 (!)
as in the figure, the specimen is reactive for antibodies to HIV-1 |
 |
 |
|
| Invalid
result |
| If
no color band appears in the control © within the stipulated time
then the result is invalid |
 |
|
| Limitations
of the test |
| Although
a positive result may indicate infection with HIV-1 or HIV-2 virus, a
diagnosis of AIDS can only be made on clinical grounds, if an individual
meets the case definition for AIDS established by the Centers for Disease
Control, For samples repeatedly tested positive, more specific supplemental
tests must be performed. Immunochromatographic testing alone cannot be
used to diagnose AIDS even if the antibodies against HIV-1/HIV-2 are present
in a patient specimen. A negative result at any time does not preclude
the possibility of HIV-1/ HIV-2 infection. |
| Performance
Characteristics |
| Sensitivity
and Specificity |
Aids
test rapid HIV Card Test 1-2.O test have tested with positive and negative
clinical samples tested by a leading commercial anti-HIV 1& 2 Elisa
tests. The result shows that the Aids test rapid HIV card test 1-2.O tests
is very accurate to other commercial Elisa kit.
In a comparison of the Aids test Rapid HIV Card Test 1-2.O test versus a leading commercial anti-HIV 1&2 ELISA and Rapid test, results gave sensitivity of 100% (120/120), a specificity of 99.18% (121/122)and total agreement of 99.59% ( 241/242).
|
| Reference |
Aids
test Rapid HIV Card Test 1-2.O |
Total
Results |
| Methods |
Results |
| Commercial
ELISA |
Positive |
| Negative |
|
| Positive |
Negative |
| 120 |
0 |
| 1
(Indeterminant) |
121 |
|
|
| Total
Results |
121 |
242 |
|
| Precision |
|
Within run precision was determined by using 10 replicates of four
different specimens containing different concentrations of antibody.
The negative and positive values were correctly identified 100% of
the time. |
|
Between run precisions was determined by using the four different
specimens containing different concentrations of antibody in 3 different
replicates with 3 different lots of test devices. Again negative and
positive results were observed 100% of the time. |
|
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