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Transcript of Prime diagnostics
1
CHARACTERISTICS OF THE KITS
◙EASY DELIVERY AND HANDLING OF SAMPLES
◙STANDARDIZED EXCLUSIVELY FOR FILTER-PAPER
◙HIGH SENSIBILITY AND SPECIFICITY
◙MANUAL AND AUTOMATIZED PROCEDURE .
◙SAME COST OF SOROLOGIC TECHNIQUES
◙FORMAT FOR SMALL, MEDIUM AND BIG ROUTINE
◙VALIDATED AT NATIONAL AND INTERNATIONAL INSTITUTIONS
DISEASES THAT MAY BE DETECTED
AIDS
HTLV
SYPHILIS
BARBER BUG FEVER
RUBEOLA
HEPATITIS B
HEPATITIS C
TOXOPLASMOSIS
CYTOMEGALOVIRUS
PRENATAL DIAGNOSIS
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The Prenatal Program is characterized by the development of preventive and corrective actions through the frequent
and planned contact of the pregnant woman with the health services, making possible the precocious intervention to
problems that affect pregnancy and the future new-born baby. The main goals of the Prenatal Program are:
-to prepare a pregnant woman to maternity by giving instructions on the parturition and on child cares.
- to give orientations on hygienic habits during the pregnancy and Prenatal moments
- to avoid medicines or actions that may damage the fetus
- to treat the small usual disturbs of pregnancy
- to make prophylaxis, diagnosis and treatment of illness and diseases that are peculiar to pregnancy
-to give psychologic assistance to the pregnant woman.
In Brazil, one of the current main concerns of Health Institutions related to women and child is to assure a better
access, a treatment and a good quality of the Prenatal assistance, especially in relation to laboratorial examinations
for controlling infectious deseases that may be transmitted from mother to her new-born son before, during and after
the pregnancy.
Although the main priorities of Health autorities and institutions are especially concentrated on AIDS and Syphilis
problems in Brazil, hospitals are still in great difficulty to provide laboratorial diagnosis of HIV infection and the
number of pregnant women examined is scarce, especially in the places where population is more vulnerable to HIV
and undergoing a bad prenatalsituation.
SITUATION OF AIDS AND SYPHILIS IN BRAZIL
-80% of HIV contaminations in people with 13 years of age occur by vertical transmission
-65% of vertical transmission of HIV occur during parturition work
-The assistance of diagnosis of HIV during prenatal period in lower than 60% and in the case of syphilis it is
only 10%
-The prevalence of Syphilis during pregnancy attains 2%
-The rate of Syphilis vertical transmission is higher than 70%
-In 2006 Brazil has shown a rate of 3.141 congenital syphilis cases
-The mortality rate for congenital Syphilis disease is high and it rather attains 40% of the cases.
At present, a few factors related with the lack of health infra-structure out of the large cities are limiting the
implementation, assistance and efficiency of field epidemiologic studies and programs of population diagnosis in
countries under development, starting from the difficulty to obtain the samples through the traditional means of
collection (periferic blood), that requires nurses or qualified personnel, as also discarding articles like test-tubes,
syringes, injection needles and the blood samples obtained through veins must be centrifugated and refrigerated.
3
PROJECT Q-PREVEN
The use of filter-paper is a cheap and a convenient method for collecting , stocking, conveying, handling and keeping
for long periods blood samples to be used in populational studies and in programs of sociologic assistance . This has
been demonstrated by the experience and by the results of the new-born diagnosis programs carried out during the
last 40 years with a group of great diseases
which included heredo-metabolic illness and infectious illness. Thanks to the use of this kind of samples, these
programs have shown a good performance, even in less developed countries and in remote regions with no
laboratorial support, so it has been possible to make diagnosis of several congenital and hereditary diseases, affording
the elimination or diminution of the associated sequels of each single illness, thus representing a great goal in
Prevention Health Programs
With a view to attain theses goals, a team of researchers highly experienced in the incrementation of products for
diagnosis of blood collected on filter paper, together with producers of material for diagnosis in vitro, started, in 2002,
the development of diagnosis kits lines based on the methodology of ELISA (immunization-test), that utilizes
samples of human blood collected on filter-paper S & S903 for analysis of infectious diseases.
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Characteritics Serum Filter-paper
Local Complex stucture No great requirements
Extraction Syringe - needle Small paint
Prepartion Centrifugate - Tube Dries at ambient temperature
Transportation Refrigerated Conventional post office
COMPARISON BETWEEN COLECTION IN SERUM AND IN FILTER-PAPER
CONVENTIONAL ELISA
AIDS
SYPHILIS
TOXOPLASMOSIS
RUBEOLA
CYTOMEGALOVIRUS
ELISA Q-PREVEN
DISEASES INCLUDED IN Q-PREVEN PROJECT
BARBER BUG FEVER
HEPATITIS B
HEPATITIS C
HTLV 1+2
5
PRENATAL PROGRAM BY USING SAMPLES ON FILTER-PAPER
Collection Kit
Lancet
Collection card (filter-paper)
Alcohol
Gloves, sterilized tent, wadding
Samples Collection Health Station/Residence
Post-Office
Pre-paid
6
IN FINAL PHASE OF DEVELOPMENT
“THE FIRST LINE OF KITS FOR DIAGNOSIS OF INFECTIOUS DISEASES
STANDARDIZED EXCLUSIVELY FOR SAMPLES ON FILTER-PAPER”
test DISEASE REGISTRATION AT ANVISA
Q-Preven Toxo IgM Toxoplasmisis Approved
Q-Preven Rubeola IgM Rubeola Approved
Q-Preven CMV IgM Cytomegalovirus Approved
Q-Preven HIV 1 + 2 AIDS Approved
Q-Preven Syphilis (total) Syphilis Approved
Q-Preven HBsAg Hepatitis B In final course
TEST DISEASE
Q-PREVEN Barber Bug Fever Barber Bug Fever
Q-PREVEN htlv 1+2 HTLV
Q-PREVEN HCV Hepatitis C
Q-PREVEN Ant Hbc Hepatitis B
Q-PREVEN Syphilis IgM Congenital Syphilis
CURRENT SITUATION OF Q-PREVEN PRODUCTS
REGISTRATION AT ANVISA
7
SPECIFIC OBJECTIVES
● To facilitate the access of pregnant women to Prenatal exams
● To ameliorate the knowledge of epidemiologic profile of aggravations in this group, in order to help interventions
● To ameliorate the quality of woman’s health,
● To ameliorate the health quality of new-born children and reduce infantile mortality
● To increase the quantity of pregnantwomen examined on Prenatal prioritary pathologies
● To reduce the prevalence and vertical transmission of the identified pathologies , especially:
HIV,Syphilis,Hepatitis B, Toxoplasmosis, Cytomegalovirus, Rubeola, etc. ●To improve the registrations and control of pregnant women
● Conception: Mass analysis
● Program target: 100% of pregnant women
● Methodology: Dry blood collected on filter-paper
● Purpose: Reduction of maternal-infantile morbi-natality
● Justification: □ High rate of maternal mortality
□ 1990: 47,8 / 100.000 parturitions
□ 2000: 53,7 / 100.000 parturitions
□ High rate of malformation, spontaneous abortion
● Essentially Preventive Program
PROGRAM PHILOSOPHY
8
Report (-)
Report +/ -
Neonatal
Service
Mother and
Baby Service
Mother and Baby
Cares
Epidemiology
Center
Reference
Laboratory
Surveillance
Laboratory
Collection
Post
Pregnant
Woman
Minicipal Secretariat of Health
State Secretariat
of Health
Ministry of
Health
Results +/-
Assistance
2nd
sample
Card
creation
Results
collection
2nd S.
sample
Sorologic sample
Final results
Sorologic sample
Results
Funds
PRENATAL PROGRAM - LOGISTICS
9
TOXOPLASMOSIS Toxoplasmosis is an infectious disease caused by a protozoa called Toxoplasma gondii. This protozoa is easily found in the nature and it can cause infection in a great number of mammifers and birds all over the world. In human beings the infection is assymptomatic in 80 to 90% of the cases, namely, it does not cause any symptom and it may be ignored in patients with a normal immunity. It is estimated that 60% of the Brazilian Pregnant women has already caught toxoplasmosis before pregnancy. The infection may be caught in several ways: by eating underdone meat, non-filtered water, vegetables and greens wrongly washed. However, The major source of transmission source of this infection is through a contact with animals (dogs and especially cats). If this infection is caught during pregnancy, it may be transmitted to the baby. When this occurs, the greatest part of the babies stay healthy but a small part will show symptoms of the disease that will become serious if the infections has been caught precociously. Nevertheless, today there are exams that allow the doctor to know if the baby is infected or not and there are medicines that are efficient and heel the baby during the woman pregnancy, reducing the probability of occurring serious problems. RUBEOLA It is an infectious disease caused by a virus (togavirus of Rubivirus type) that attacks children and adults, although it is considered a disease of children. Although it is considered a viral disease, generally a benign virus, when it occurs during the pregnancy it may be transmitted to the fetus, and become serious causing intra-uterine death or malformations. The diffusion Of vaccine diffusion has diminished the incidence of congenital rubeola that presently is estimated in 4/10.000 gestações. Rubeola may be transmitted through the inalation of small drops of nose secretion of people bearing the virus, or via blood, in the case of afetus, during pregnancy. The disease in a baby is more serious when caught precociously in the pregnancy. During the three first months, more than 80% of maternal infections of rebeola are transmitted to the baby, and there is 20% of abortion risk or a serious congenital malformation in 90% of the risks. The risk of fetal transmission diminishes progressively after the 3
rd month and the risks of malformation is practically null after the fourth month.
CYTOMEGALOVIRUS (CMV) The cytomegalovirus is an timeserver human pathogene where the infection is particularly prevalent between children and young adults. The infection through CMV is an important health problem in certain groups of patients, as new-born babies, patients who have undergone solid organs or bone medule transplantation and bearers of AIDS. The congenital cytomegalovirus is a most frequent infection. It is estimated that in Brazil 0,55% to 6,8% of the babies come to life contaminated with cytomegalovirus and between the infected babies 5 to 20% show the symptoms when they are born (pneumonia,low weigh,prematurity, neo-natal ictericia). The infection may cause permanent problems in the baby, especially a delay in the development and a mental retardation. The transmission of the virus to the baby occurs normally as a result of an acute mother infection. If there is a contact with the virus, confirmed through laboratorial exams, the Prenatal diagnosis of the fetal infection may be done through the amniotic exam that may be performed from the 6
th month on of pregnancy
10
AIDS The Syndrome of Acquired Imuno-Deficiency (AIDS) has been described for the first time in l981 and it is an infectious disease caused by the virus of human imuno-deficiency which leads to a progressive loss of immunity, ending in serious Infections, malign tumours and other timeserver infections that may take to death.
From 1980 to June 2005, statistics have shown 371.827 cases of AIDS in Brazil. In general the incidence rate of AIDS
(cases of disease per each 100 thousand inhabitants) keeps stable, but in 2004 it has attained - 17,2. The difference between
men and women rates is changing considerably and today we have 1,5 male cases per 1 female case. In the beginning of
the epidemy, the comparison was 16 male cases against 1 female case.
The HIV virus may be transmitted through sexual contact between infected people with HIV, through exposition to blood
(including the shared use of contaminated injection needles) or through certain hemoderivated contaminations with HIV or
then through mothers transmission to their fetus or baby during prenatal period.
The transmission of virus from mother to son stands for the majority of AIDS cases among children. A due treatment of
HIV+ in pregnant women allows to save up to 70% of the babies and they will have a good chance to come to life without
the virus.
SYPHILIS
Syphilis is a chronic infectious disease caused by a fragile bacteria called Treponema Pallidum which grows in a chronic
(slow) way and shows acute periods (it burst out acutely) alternated with latent period (with no manifestation).
If it is not treated in time, it grows up and becomes chronic and ostensive, affecting multiple organs (skin, eyes,bones,
cardiovascular system, nervous system). Its progression, according to the body injure degree, has been classified in several
stages (primary, secondary and tertiary). The two first stages show stronger characteristics of infection with more symptoms
and more risk of contamination. Syphilis may be caught by sexual contact, via placenta (congenital syphilis since foetus is
attacked during intra-uterine life), via kiss or other intimate contact with an active wound (containing bacteria Treponema),
via blood transfusion or other derivated ways.
Main aspects to be taken into account in the vertical transmission of syphilis:
● the maternal transmission may occur in any pregnancy period;
● The rate of vertical syphilis, in women without any treatment, stands between 70 to 100% during the first 4 years of the
disease evolution;
●Prenatal death occurs in 40% of the infected babies
A correct treatment during pregnancy reduces to 1,5% the risk of syphilis transmission to the baby.
11
HEPATITIS B
Hepatitis B is an infectious disease caused by a virus which affects essentially the liver. Hepatitis B (HBV) virus may
cause an infection for the rest of the life, like liver cirrhosis, liver cancer, hepatic failure and death. After the infection,
the virus concentrates almost totally into the cells of the liver.
Hepatitis B may be caught through blood transfusions or shared utilization of syringes, needles and other instruments
of drug users, or also in sexual relations,body contacts with secretions contaminated with the virus,mucus orwounded ]
skin and also by vertical transmission from the pregnant to the baby.
The transmission risk is little during the first and second quarter of pregnancy but it is high after the 7th month. Other
vias of contamination are the contact with maternal blood or contaminated vaginal secretions during the parturition or
through mother’s milk.
The incidence of Hepatitis B during pregnancy is around 0,5%. The baby may catch the infection from a pregnant
woman with a strong infection or chronical carrier of hepatitis.
BARBER BUG FEVER
Barber Bug Fever is as infectious and parasitary disease caused by the protozoe Trypanosoma Cruzi and transmitted
by the insect Triatoma infetans (Triatomineo), commonly called Barber. It is an endemic disease of great part of
Central and South America. According to the World Health Organization, around 17 million people are carriers of
Barber Bug Fever and 50.000 of them die every year. In Brazil, approximately 5% of the population carries this
disease and the statistics show 100.000 new cases per year.
The main vias of transmissions are:
Vectorial: prick of infected triatomineo
Transfusional: exposition to contaminated blood
Transplacentary: vertical transmission from a mother to the new-born baby.
A pregnant woman carrying this strong or chronical infection may transmit it to the foetus in any period of her
pregnancy, including during the first quarter, if the trophoblasto is thicker, and even in the channel of parturition
through the contact of foetus mucus with his mother’s infected blood.
The incidence in pregnant women may vary from 2 to 11% in the urban centers and from 23 to 58% in the rural
areas. Studies have been published saying that in new-born babies the incidence may vary from 0,7% to 8% and
the transmission is 1% among chronical carriers and 7,7% among premature babies of carriers women.
HEPATITIS C
Hepatitis C is a liver disease caught through the contact with infected blood or other body fluids. It is caused by
virus HCV and in the past it was called virus non-A/non-B. Hepatitis C is dangerous because in 85% of the cases it
becomes chronic and may grow and become a liver cirrosis or cancer. The evolution period of the disease is estimated
to be 20 to 30 years but each single organism react differently. This period depends on the cares and modus vivendi
of the patient. It is estimated that among 2,5% to 4,9% of the Brazilian population, approximately 4.1 to 8 million
people are carriers of Hepatitis C.
12
The transmission of Hepatitis C occurs through the contact with the blood or body contamined secretion: blood,
mucus or wounded skin. Although recent reports mention the presence of this virus in other secretions (milk, spittle
,urine and sperma), the quantity of virus seems to be too little to cause infection and there are no data indicating
transmission through these vias. The mother-foetus transmission is rare. In spite of the already known transmission
means, 20 to 30% of the cases occur without revealing the contamination via.
HTLV 1+2
HTLV is a virus pertaining to the family of retrovirus (the same as HIV). HTLV 1 causes mainly a rare modality of
leukaemia (Leukaemia of Cells T in adults) which is normally fatal and a serious chronical neurologic degenerative
disease, myelopathy/paraparesis that affects the capacity of walking.
It is estimated that 15 to 20 million people in the world are carriers of HTLV-1. In Brazil, statistics show 2,5 million of
infected people by this virus, especially in Bahia (1,35% to 1,80% of the population), Pará (1,61%) and Pernambuco
(0,33% to 0,82%). Nevertheless, just as in the rest of the continent, these information is based on studies of specific
groups like blood donors and pregnant women.
Among the strategies to diminish the incidence of HTLV in Brazil , there is the implantation of binding tests for
detecting HTLV in milk banks and prenatal exams.
HTLV is transmitted similarly to HIV, namely through body fluids like sperma, vaginal secretions, blood, pregnant
women to fetus and baby nursing.
14
“EVALUATION OF Q-PREVEN HIV 1+2 TEST
SPECIFICALLY DEVELOPED FOR DETECTING
ANTIBODY TO HIV 1+2 IN SAMPLES OF DRY BLOOD”
Laboratory of HIV/AIDS Researches
UCS/ Caxias do Sul – RS
Caxias do Sul/February 2005
16
“EVALUATION OF THE PRENATAL EXAMS OF HIV
BY USING DRY BLOOD ON FILTER PAPER” APAE – Associação de Pais e Amigos dos Excepcionais de Salvador
Salvador – Bahia State
17
APAE ASSOCIATION PRESENTS A NEW EXAM FOR DETECTING AIDS IN
PREGNANT WOMEN
04/11/2005 – 09h50
the unique service entitled by the Ministry of Health to perform the child foot test may now become a reference
also in the detection of HIV virus in pregnant women. The Association of Parents and Friends of Anomalous –
APAE – has presented yesterday, in Salvador city, the validation of a new technique of collection and analysis of
exam that utilizes the same material as the one of child foot test: filter-paper. It reduces the time of diagnosis
(8 days instead of 60) , it costs 30% less and finally the procedure may increase the access of pregnant women to the
exam and favour the tracing of other maternal diseases subject to vertical transmission.
The researchers of the Reference Service for Newborn Surveillance of APAE worked during 6 months for the
validation of the technique created last year. In partnership with The Health Secretariat of the State of Bahia
(Sesab) they have submitted to analysis 1.483 patients who asked for Prenatal assistance in 3 public Maternity
hospitals (Albert Sabin, Tsylla Babino and Iprba) , as also in the Reference Center specialized in DST/AIDS of
Salvador and in APAE. The results which included also tests with 25 blood tests of patients soropositive (sent by the
Hospital Efgard Santos) showed that the traditional method matches 99,86% with the filter paper methodology.
Preconized by the Ministry of Health the serologic methodology for HIV detection in pregnant women is only
favoured by the new technology. Any health station making the test of child foot is in a position to perform the
material collection for the HIV exam with samples o dry blood and send it even by envelope to the laboratory of
analysis. “The collection may be done in any place of the State, within the same routine of diagnosis of Prenatal
cases. The facility and simplicity of the procedure favour what recommends the Ministry of Health: the universal
access to the exam”, says the medical director of APAE, Dr Cleusa Zanetti.
Source: Correio da Bahia (journal)
20
DIAGNOSIS OF HIV
15/01/2005 – 09:45
Brazilian Researchers Point Out Advantages Of Filter-Paper in HIV Diagnosis
BRASILIA – Researchers of the University of Caxias do Sul (UCS) have developed a study for validating and
evaluating the advantages of a “test with dry samples on filter paper”, a technology that allows to check if the
patient has the virus HIV and other diseases by analysing a small sample of blood dropped on a paper from a prick
on a patient’s finger. The research, financed by the National Program of DST/AIDS and by the Orgnization of the
United Nations for Science and Culture (UNESCO), examines the filter paper in different conditions of temperature
and moisture, comparable to cities of other regions of the country, and this will serve for the government to analyse
its utilization in regions of difficult access or with little laboratorial structure.
According to the Chief of the Researches Laboratory in HIV and AIDS of the University UCS, Dr Ricardo da Silva de
Souza, the results of the first phase of research have been quite positive. The validation confirmed that filter paper has
the same efficiency of the collection via veins injection and he pointed out other factors of security.The evalutation of
the sensibility of filter paper for tests anti-HIV (capacity of giving positive results) showed 100% of efficiency and
the one of specificity (capacity of identifying people without the virus) has showed 99,5% of favorable results.
The doctor who coordinated the research said that in the overall they have analysed 309 samples between the 3rd
of
December 2004 and the 3rd
of January 2005. “We have been able to certify that it is possible to make a diagnosis of
HIV with filter paper and we could realize that it works. It has a stability of up to 35 days without special conditions
of stockage, namely, it fits the ambient temperature”, he assures. Today only one company has the registry at
National Sanitary Agency (ANVISA) for the utilization of filter paper as a method of blood collection and it is not
binding to present a study of stability to the regulating agency.
ADVANTAGES
Beside validating the method, the researchers showed other positive points of this kind of sampling, like the easy
collection and storage, the necessity of little structure and little human resources, as also the capacity of generating
quick answers (via internet and post office) and the low .cost. “The transport of conventional samples of blood (via
tubes of tests) may alterate the characteristics of blood if there is not an dequate refrigration and there is also the risk
of accidents with the material. With filter paper the transport may be done by post office without any alteration of
the results”, he says. In the traditional method, if the blood is not refrigerated right after the collection, says Ricardo,
it is annulled . “We reproduce the conditions of collection and transport and we confirm that the exams may be
tested with quality even after a long period after analysis and with variation of temperature and moisture.”
The variation of moisture is an important point because the sample is dry and if the weather is too humid, it may
generate fungus and other problems that interfere in the result. Variations of temperature and moisture of Porto
Alegre city have been compared to other seven capitals (Curitiba, João Pessoa, Manaus, Natal,Rio Branco,Salvador
and Teresina), where it has been noticed a similarity between them and the absence of any difference in the results
and in the quality of the samples due to the temperature and moisture aspects. Therefore, the samples can come from
any place of the country without alterating the results of the exam.
Although it was not one of the objective of the research, the researchers made preliminary analysis of the results
confirmation by comparing the initial information made through the method Elisa with the Western Blot, one of the
exams that confirms HIV.” It was not our principal objective but we could confirm that the Elisa results are the same
as the Western Blot ones. However, we saw in these preliminary results that it is important to have a higher quantity
of dry blood than the one used in Elisa, leaving the test more sensible due to the size of the sample, namely the ideal
is to use two samples of dry blood for each patient in the confirmatory” says the coordinator of the research.
21
PILOT
The researchers finalized the first phase of the project that started in April 2004 and are expecting to start the following
phase still in the first semester of this year. At this stage will be performed a pilot-study in Prenatal hospitals and different
regions of the country to check if the data shown in phase 1 are confirmed in phase 2. “We want to develop an algorythm
specific for filter paper in testing HIV, namely we want to have a sequence of tests that would give 100% of chances to
obtain the correct result with this method”, defends Ricardo.
Another objective of phase 2 is to implant the system of devolution of the results by internet and post office and offer
training courses personally and at distance, in order to orient the professionals health on how to present the result to the
patients.
According to the researcher, the idea is to associate the diagnosis via filter paper to other programs, such as the Family
Health, and serve as instrument of diagnosis of other infections that attack pregnant women. “For this reason we have
started to validate and test filter paper for toxoplasmosis, cytomegalovirus, syphilis, herpes, rubeola and HTLV”. The
intention of this study is to contribute for the reduction of the vertical transmission (when the virus passes from a mother
to her baby) and other prenatal infections through precocious diagnosis afforded by the test.
22
„PERFORMANCE OF TESTS AVAILABLE IN BRAZIL
FOR THE DETECTION OF ANTIBODIES
ANTI-HIV 1 + 2 IN FILTER PAPER SAMPLES”
Laboratory of Research in HIV/AIDS UCS/Caxias do Sul-RS
Caxias do Sul / February 2005
HEALTH
23
INTRODUCTION:
The advantages shown, especially in the programs of neonatal assays, on the use of the technology based on blood
samples collection on filter paper, have directed the attention to the employment of this method in diagnosis tests.
Among all the advantages already compared, it is known that samples on DBS (dried blood spot) show a diagnostic
stability of at least 6 weeks in room temperature for the detection of antibodies However, there are very little tests
available in the market for the use of this methodology of collection in the laboratorial routine.
OBJECTIVE
The objective of this study hs been to evaluate the performance of tests commercialized in Brazil for the detection
of antibodies anti-HIV 1 and 2 on dry samples of blood collected on filter paper and stored for a period of 6 weeks
and more than 6 weeks.
MATERIALS AND MEHODS
The performance of tests Q-Preven HIV 1 + 2 -DBS (Q-=Prevenen diagnosis) and Umesalisa HV 1 and 2 Recombinant ®
(Tecnosuma) have been evaluated. For the evaluation of the tests a panel of samples on DBS has been used. This panel has
been obtained from the transference of 50 ul of whole blood collected in a tube of collection with EDTA for collection card
S&S 903 containing 5 circles of around 13 mm of diameter. All the samples showed l known serologic status of HIV
presence in the serum (Tab.1). The testing moments of the samples were diversified in samples stored for period of up to 6
weeks (n=339 Q-Preven and n=61 Umelisa) or for more than 6 weeks (n=76 Q-Preven and n=309 Umelisa). During this period
the samples were stored at room temperature inside of a plastic ziplock bag with dissecant. All the results obtained for DBS
were compared with the sorologic status of the panel samples. The average monthly local moisture have been observed during
the period of storage of the samples (Fig.1)
Table 1 – Panel HIV 1 & 2 of blood samples
collected on filter paper
Sample Q-Preven Umelisa
Positive 168 140
Negative 247 230
Total 415 370
Picture 1 – Monthly average of maximum and minimum relative moisture recorded into the storage place of the samples panel.
Performance of available tests in Brazil for
detecting antibodies anti-HIV on filter paper
24
RESULTS AND DISCUSSION
The results were favorable to the method of diagnosis involving dry blood collected on filter paper. None of the
samples showed an indetermined result in the tests Umelisa (Tab.2) and Q-Preven (Tab.3) The two results false-
positive (samples 26N and 204N) and Q-Preven (Tab.4), when submitted to a triple repetition, showed concordant
results, showing a specificity of 100% in one repeated test. The test Umelisa HIV 1 and 2 (Tab.4) showed a result
false-positive (sample 122N) and one false negative (sample 47P). Both the results kept discordant when repeated in
triplicate. A superior sensibility has been shown on the tests Q-Preven in relation to Umelisa when observing the
result of the test of final point of detection for dilution in series in a same sample, for both the tests.
Table 2. Result obtained with panel of samples Table 3. Result obtained with panel of samples
tested for kit Umisa HIV 1 and 2 Recombinant tsted for kit Q-Prevent HIV 1 and 2 - DBS
Storage Negative Positive Total Storage Negative Positive Total
◄ 6 weeks 30 31 61 ◄ 6 weeks 204 135 339
► 6 weeks 200 109 309 ►6 weeks 41 35 76
total 230 140 370 245 170 415
Table 4. Performance of tests anti-HIV on samples panel
TESTS
Q-Preven
◄ 6 weeks ► 6 weeks
UMALISA
◄ 6 weeks ► 6 weeks
False positive 2 0 0 1
False negative 0 0 0 1
Sensibility 100% 100% 100% 99.5%
Specificity 99% 100% 100% 99,1%
VPP 1 1 1 0,99
VPN 0,98 1 1 0,99
CONCLUSIONS
The two evaluated tests of antibodies detection showed satisfactory results. Both of them showed qualification for
being applied on samples diagnosis of whole dry blood, when employed in an algorythm of tests following the
patterns established by the Ministry of Health.
REFERENCES:
26
ASK DR TABORDA
Edition 166 – Sept./07
Child foot Test for Pregnant Woman
The utilization of this alternative method is always more diffused and it consists in collecting
blood samles of pregnant women and trace infection during prenatal period, so that it enables
to reduce de risk of transmitting HIV, syphilis,cytomegalovirus,toxoplasmosis and hepatitis B.
The blood is collected with only one prick in the finger – similarly to the process renown as
“child foot test” made in new-born children – and stored on filter paper.
The method is cheap and it dispenses with qualified professionals for collection, storage and
transport. The difficulty for obtaining blood samples is just one of the points that contributes
to the high Brazilian transmission of diseases from mother to child. The strategy consecrated
all over the world is to obtain prenatal exams in order to identify transmissible diseases but
unfortunately this does not attain great part of pregant women. Currently, around 80% of
teenagers under 13 years of age have been contaminated during the preganancy or parturition
or nursery. A shameful panorama. Several researches confirm the good application of filter
paper.
This technology has been used at APAE, in Bahia, to trace the HIV in approximately 1.500
pregnant women and the result has been the same as those of traditional tests in 99,86% of
the cases.
Edition 166 09-2007
Wladimir Taboarda is Doctor in Medicine at the Federal University
of São Paulo, as also Consultant of the Hospital and Maternity São Camilo in São Paulo