Download HOW TO DIAGONISE HIV INFECTION

HOW TO DIAGONISE HIV INFECTION
Appelles Ohanga-Too
HIV/AIDS prevention and management
Spring 2015
Diaconia University of Applied Sciences
Masters-Degree Programme in global
healthcare
According to WHO webpage human immunodeficiency virus (HIV) is a retrovirus that infects
cells of the immune system, destroying or impairing their function. As the infection
progresses, the immune system becomes weaker, and the person becomes more
susceptible to infections and eventually the most advanced stage of HIV infection which is
acquired immunodeficiency syndrome (AIDS). HIV is transmitted through unprotected
sexual intercourse (anal or vaginal), transfusion of contaminated blood, sharing of
contaminated needles, and between a mother and her infant during pregnancy, childbirth
and breastfeeding.
Justine et al 2001 states that symptoms play a central role in the patient’s experience of
disease. They are the primary reason a patient seeks care, and a determinant of the
patient’s perceived health related quality of life. According to WHO symptoms of HIV vary
depending on the stage of infection. Though people living with HIV tend to be most infectious
in the first few months, many are unaware of their status until later stages. The first few
weeks after initial infection, individuals may experience no symptoms or an influenza-like
illness including fever, headache, rash or sore throat. As the infection progressively weakens
the person's immune system, the individual can develop other signs and symptoms such as
swollen lymph nodes, weight loss, fever, diarrhoea and cough. Without treatment, they could
also develop severe illnesses such as tuberculosis, cryptococcal meningitis, and cancers
such as lymphomas and Kaposi's sarcoma, among others.
HIV TESTING AND COUNCELLING (HTC)
WHO webpage indicates that HIV testing and counselling (HTC) services have helped
millions of people learn their HIV status, and for those testing positive, learn about options
for long term care and treatment. HIV testing and counselling (HTC) services have helped
millions of people learn their HIV status, and for those testing positive, learn about options
for long term care and treatment. Kenya national guidelines of HIV testing and counselling
is delivering HTC through voluntary counseling and testing or provider-initiated counseling
and testing (PICT). (Annelies Van Rie, 2014) Also states that alternative approaches for
testing include contacts of index cases, mobile testing, door-to-door testing, school-based
testing can increase HIV case finding.
Provider-initiated HIV testing and counselling refers to a situation in which the HTC service
provider, who may be a health care worker or other type of HTC service provider, offers an
HIV test to a client or patient regardless of their reason for attending the facility. Prior to
receiving an HIV test, the health care provider will explain the procedure and the reasons
for requesting the test to the client or patient. Upon the recommendation of the health care
provider, if the client or patient agrees to learn their HIV status s/he will receive an HIV test
and will be informed of their results. World Health Organization (WHO) recommends PICT
for all people visiting a health facility PICT in health care facilities in high burden countries
is mainly targeted at individuals presenting for antenatal, TB or STI care . (National
guidelines for HIV testing and councelling in kenya, 2008)
Client-initiated HTC refers to a situation whereby an individual, couple, or group actively
seeks out HIV testing and counselling at a site where these services are provided and/or
accessible. Previously in Kenya this took place primarily in the context of voluntary
counselling and testing (VCT); however HTC may be initiated by clients in settings other
than VCT sites such as health facilities, mobile sites, or in people’s homes. The clientinitiated approach to HTC requires that persons wishing to know their HIV status take it upon
themselves to request an HIV test. Clients may seek HTC services to guide personal life
decision making, plan for one’s future or the future of their family, and understand symptoms
one is experiencing, or support personal HIV prevention efforts.
Screening tests for HIV and Diagnosis
According to the center of disease control (CDC), there are three types of HIV diagnostic
tests: antibody tests, antigen/antibody tests, and nucleic acid (RNA) tests. Antibody tests
detect antibodies, proteins that your body makes against HIV, not HIV itself. Antigen tests
and RNA tests detect HIV directly.
CDC continues to state that an initial HIV test will either be an antibody test or
antigen/antibody test. It may involve sending blood or oral fluid to a laboratory or obtaining
blood or oral fluid for a rapid test. Blood tests can detect HIV infection sooner after exposure
than oral fluid tests because the level of antibody in blood is higher than it is in oral fluid.
Likewise, antigen/antibody and RNA tests detect infection in blood before antibody tests.
Some newer antigen/antibody lab tests can sometimes find HIV as soon as three weeks
after exposure to the virus. No antigen/antibody or RNA tests are available for oral fluid.
Follow-up testing is performed if the initial test result is positive. HIV tests are generally very
accurate, but follow-up testing allows you and your health care provider to be sure the
diagnosis is right. If your initial test is a rapid test and it is positive, you will be directed to get
follow-up testing. If your initial test is a laboratory test and it is positive, the laboratory will
usually conduct follow-up testing on the same blood specimen as the initial test.
Follow-up tests include:

antibody differentiation tests, which distinguishes HIV-1 from HIV-2 antibodies;

HIV-1 nucleic acid tests, which looks for the virus RNA directly;

Western blot and indirect immunofluorescence assay, which detect antibodies.
Currently the most sensitive screening tests are so-called fourth-generation assays (Ag/Ab
assays), which detect both HIV antibodies and p24 antigen simultaneously and thereby
shorten the window period during which an individual may be infected but antibodies are not
detectable. British association for sexual health and HIV guidance (2010) states that
although a negative fourth-generation HIV test 4 weeks after a risk exposure is ‘very
reassuring”, an additional HIV test should be offered at 3 months. In addition, patients taking
28 days post-exposure prophylaxis (PEP) following a significant risk need to wait the usual
12-week window period, as the PEP may suppress p24 antigen production.
Measurement of HIV RNA (viral load) is not usually recommended as a diagnostic assay
due low-level false-positive results. However it is used to monitor therapeutic response and
can be useful in the diagnosis of early infection before the production of antibodies.
Some of the dilemmas for screening HIV performed using serological assay is false positive
serological results in HIV and also other diseases. False-positive results with enzyme
immunoassays are known to occur in many diseases/situations including multiple blood
transfusions, hypergammaglobulinemia, history of recent vaccination, multiple pregnancies,
hemodialysis, antibodies to HLA antigens, autoantibodies associated with autoimmune
diseases, and cross-reactivity with vector proteins amongst others. (Sujoy Khan, 2014)
Rapid test is an immunoassay used for screening, and it produces quick results, in 30
minutes or less. Rapid tests use blood or oral fluid to look for antibodies to HIV. If an
immunoassay (lab test or rapid test) is conducted during the window period (i.e., the period
after exposure but before the test can find antibodies), the test may not find antibodies and
may give a false-negative result. All im munoassays that are positive need a follow-up test
to confirm the result.
Rapid tests may be applied in the following settings:

Antenatal clinics when the mother presents late. Rapid test supports decision in the
use of antiretroviral therapy to prevent mother-to-child transmission of HIV.

Settings where a high risk of needle-stick injury is expected. Rapid test of the source
patient and victim, with informed consent, informs the decision to use prophylaxis.

Outreach setting where conventional HIV testing may not reach certain vulnerable
populations such as drug users, sex workers and men having sex with men.

Conventional HIV care setting where there is a high defaulter rate. Instead of the
traditional two sessions, only one is required for those who test negative.
The test is not intended for use by the general public. It is done by medical professionals
and requires the same standard as conventional HIV antibody tests. However,
counselling techniques may need to be adapted depending on the settings.
Home Access HIV-1 Test System is a home collection kit, which involves pricking your
finger to collect a blood sample, sending the sample to a licensed laboratory, and then calling
in for results as early as the next business day. This test is anonymous. If the test is positive,
a follow-up test is performed right away, and the results include the follow-up test. The
manufacturer provides confidential counseling and referral to treatment. The tests
conducted on the blood sample collected at home find infection later after infection than
most lab-based tests using blood from a vein, but earlier than tests conducted with oral fluid.
Diagnosis of infection in infants requires the use of NAAT tests since antibodies detected
may be of maternal origin. Using fourth-generation assays these antibodies may be detected
beyond 18 months of age. DNA or RNA/viral load assay may be used. mothers is to test the
infant (Catherine A Ison, 2015)
Indications for a diagnostic HIV test
For individual diagnosis, the standard testing algorithm is the two-step use of ELISA for
screening and WB for confirmation. The requesting physician should ensure that all tests
are done in a quality laboratory. An HIV diagnostic test is indicated in people at risk of the
infection, including persons with:

Behavioural risks of and potential exposure to HIV infection, such as injecting drug
use, any form of cocaine use, male-male sex, multiple sexual partners, and
commercial sex. All sex partners of persons with these risk factors are also at risk.

Occupational exposure to a possibly infected source, normally referring to that in the
health care setting such as after a needlestick injury.

Other sexually transmitted infections (STI) - It is known that either ulcerative or nonulcerative STI facilitates HIV transmission.

Clinical conditions associated with HIV infection, varying from classical AIDS-defining
conditions to tuberculosis, herpes zoster in a young patient, oral thrush, unexplained
fever, and lymphadenopathy.

Receipt of blood or blood products between 1978 and 1985, the year when screening
of donated blood and organs began in Hong Kong. (Diagnostic Laboratory Testing
for HIV Infection in the United States, 2012)
REFERENCES
A. C. Justice, C.H. Chang, Rabeneck. L, Zackin R. ( 2001). Clinical Importance of
Provider-Reported HIV Symptoms Compared With Patient-report, Volume 39(4) pp
397-408.
(2008). National guidelines for HIV testing and councelling in kenya. Nairobi: Ministry of
Public health and sanitation.
Diagnostic Laboratory Testing for HIV Infection in the United States. (2012). United states:
center for disease control (CDC).
Annelies Van Rie, K. C. (2014). High Uptake of Systematic HIV Counseling and Testing
and TB Symptom Screening at a Primary Care Clinic in south africa. PLOS ONE
www.plosone.org.
Catherine A Ison, J. T. (2015). Laboratory diagnosis of sexually transmitted infection.
www.medicinejournal.co.uk.
Sujoy Khan, S. S. (2014). Diagnostic dilemmas in human immunodeficiency virus testing.
India: Departments of Allergy and Immunology andT ransfusión Medicine, Apollo
Gleneagles Hospital,.
http://www.who.int/topics/hiv_aids/en/. Accessed 9.5.2015
http://www.cdc.gov/hiv/testing/index.html. Accessed 9.5.2015