Ability to adapt to seasonal temperature extremes among atrial fibrillation patients. A nation-wide study of hospitalizations in Israel.

BACKGROUND: In recent years, temperature fluctuations and adverse weather events have become major concerns, influencing overall mortality and morbidity. While the association between extreme temperatures and atrial fibrillation (AF) has been supported by research, there is limited evidence on the ability of AF patients to adapt to the changing temperatures. We explored this question among AF patients in Israel featured by extreme temperature conditions. METHODS: We examined the association between exposure to extreme temperatures and hospitalizations related to AF in a nationwide cohort in Israel. A case-crossover design with a distributed nonlinear model (DLNM) was applied to assess possible effects of temperature fluctuations during each season. We considered the 7 days prior to the event as the possible window period. RESULTS: During 2004-2018 we recorded a total of 54,909 hospitalizations for AF. Low temperatures in winter and high in summer adversely affected AF-related hospitalizations. The effect recorded for the first few weeks of each season was of higher magnitude and decreased or faded off completely as the seasons progressed (OR in winter: from 1.14, 95%CI 0.98, 1.32 to 0.90, 95%CI: 0.77, 1.06;OR in summer: from 1.95, 95%CI: 1.51, 2.52 to 1.22, 95%CI: 0.90, 1.65). Patients living in the south region and patients with low socioeconomic status were more susceptible to extreme temperatures. CONCLUSIONS: Although extreme hot and cold temperatures are associated with an increased risk of hospitalization for AF, the patients are likely to adapt to temperature change over the course of the first weeks of the season.

Levels of PFAS concentrations in the placenta and pregnancy complications.

BACKGROUND: Recent research has raised concerns about the potential health effects of perfluoroalkyl and polyfluoroalkyl substances (PFAS) exposure, particularly during critical periods of development such as pregnancy. In this study, we sought to investigate the presence and potential impacts of PFAS in the placenta. METHODS: We measured 13 PFAS compounds in placental tissue samples among 50 women who gave birth at a tertiary medical center in southern Israel. The sample comprised of 10 women with pregnancy-related complications (preterm birth, preeclampsia, gestational diabetes or small-for-gestational age) and 40 women without complications individually matched to cases by age. RESULTS: For five (5) out of 13 PFAS compounds (Perfluorooctane Sulfonate (PFOS), perfluorooctanoic acid (PFOA), Perfluorohexanesulphonic acid (PFHxS), Perfluorononanoic acid (PFNA), Perfluorodecanoic acid (PFDA)) median concentrations were lower or comparable to placental measurements in different international populations. Geometric mean was estimated at 0.09 ng/g (90%CI:0.07;0.10) for PFOA, 0.05 ng/g for PFNA (90%CI:0.04;0.07), 0.03 ng/g for PFDA (90%CI:0.01;0.03), 0.06 ng/g for PFHxS (90%CI:0.05;0.07), 0.23 ng/g for PFOS linear measurement (90%CI:0.20;0.26) and 0.25 ng/g (90%CI:0.22;0.30) for PFOS summed concentrations that included non-linear isomers. Composite outcome of pregnancy-related complications was associated with elevated PFOA placental concentrations at an odds ratio (OR)= 1.82 (90%CI:1.06;3.13) for an increase of one quintile of PFOA value and adjusted to maternal gravidity in a conditional logistic regression. CONCLUSION: This pilot study indicates a widespread exposure to multiple PFAS compounds in placental tissue of pregnant women in Israel. These findings warrant further validation through comprehensive national human biomonitoring initiatives.

Maternal metal concentration during gestation and pediatric morbidity in children: an exploratory analysis.

BACKGROUND: The majority of studies linking exposure to metals with certain health outcomes focus on known toxic metals. Alternatively, this study assesses the extent to which exposure to a wider range of metals during gestation is associated with childhood morbidity. METHODS: We analyzed the concentrations of 25 metals found in urine samples of 111 pregnant women of Arab-Bedouin origin collected prior to birth. In addition, we collected medical records on their offspring for six years following birth, including every interaction with HMOs, local hospitals, and pharmacies. RESULTS: The main types of morbidities diagnosed and treated during this period were preterm births, malformations, asthma-like morbidity, cardiovascular and behavioral problems, and obesity. Multivariable analysis showed that offspring born before term were more likely to have been exposed to elevated maternal concentrations of zinc, thallium, aluminum, manganese, and uranium, all with adjusted relative risk above 1.40 for an increase by each quintile. Likewise, children with asthma had been exposed to higher levels of magnesium, strontium, and barium at gestation, while behavioral outcomes were associated with elevated biometals, i.e., sodium, magnesium, calcium, selenium, and zinc, as well as higher levels of lithium, cobalt, nickel, strontium, cadmium, vanadium, arsenic, and molybdenum. A heatmap of adjusted relative risk estimates indicates the considerable implications that exposure to metals may have for preterm birth and developmental outcomes. CONCLUSIONS: The current study shows that perinatal exposure to metals is adversely associated with pediatric morbidity. Further such analyses on additional samples are warranted.

The effects of ambient particulate matter on human adipose tissue.

The effects of particulate matter (PM) air pollution on adipose tissue have mainly been studied in animal models. The aim of this study was to examine the potential associations between PM exposure and 25 cellular markers in human omental (OM) and subcutaneous (SC) adipose tissue. The PM exposure assessments for both PM2.5 (PM <2.5 µm in diameter) and PM10 (<10 µm) were based upon a novel hybrid satellite-based spatio-temporally resolved model. We calculated the PM exposure above the background threshold for 1 week (acute phase), 3 and 6 months (intermediate phase), and 1 year (chronic phase) prior to tissue harvesting and tested the associations with adipose cell metabolic effects using multiple linear regressions and heat maps strategy. Chemokine levels were found to increase after acute and intermediate exposure duration to PM10. The levels of stress signaling biomarkers in the SC and OM tissues rose after acute exposure to PM10 and PM2.5. Macrophage and leucocyte counts were associated with severity of PM exposure in all three duration groups. Adipocyte diameter decreased in all exposure periods. Our results provide evidence for significant contribution of air pollutants exposure to adipose tissue inflammation as well as for pathophysiological mechanisms of metabolic dysregulation that may be involved in the observed responses.

Association between prenatal exposure to metals and neonatal morbidity.

An association between prenatal exposure to (semi-)metals and of neonatal morbidity was assessed by introducing an oxidative stress as a possible intermediate step. An oxidative stress was measured by cell proliferation (CP) ratio in umbilical cord blood cells. Urine samples of 18 out of 58 enrolled women (31%) were positive for (semi-)metals; 25.9% of women were positive for aluminum (Al). The CP ratio was higher (1) in subjects with Al, (2) in mothers to newborns diagnosed as small-for-gestational age (p value = .052), (3) neonates that weighed less (p value = .079), and (4) in women who experienced repeated abortions (p value = .049). Our findings suggest the possibility of metal-induced oxidative stress.

Exposure to metals and morbidity at eight years follow-up in women of childbearing age.

This exploratory study was aimed to investigate the link between toxic metal content in women's urine and their morbidity 2 years before and 6 years after the test. Concentrations of 25 metals in urine were analyzed for 111 pregnant women collected prior to delivery. All women were of Arab-Bedouin origin. Information on primary care and hospital visits during the study period was obtained. In a Poisson regression model, a health outcome was regressed over metal exposure and other factors. A Weighted Quantile Sum Regression (WQS) approach was used to indicate metals dominating in their possible impact on women's morbidity. Obesity was the most frequently diagnosed condition in this population (27.9%). Diagnoses in a neurological category accounted for 36.0%, asthma or respiratory-25.2%, psychiatric-12.6%, cardiovascular-14.4% and cancer or benign growth-for 13.5%. Based on WQS analysis, cancer and benign growth were mostly attributed to the increased levels of cadmium, cardiovascular outcomes were linked with lead, and obesity was found associated with elevated levels of nickel. Hematological, neurological and respiratory outcomes were attributed to multiple non-essential metals. The health and exposure profile of women in the study warrants a periodic biomonitoring in attempt to identify and reduce exposure to potentially dangerous elements.

Anthropogenic or non-anthropogenic particulate matter: Which one is more dangerous and how to differentiate between the effects?

The authors have observed that the function linking health outcomes with exposure to particulate-matter (PM) follows a biphasic pattern. It peaks around levels of PM10≤100 µg/m3, then weakens and rises again at PM10 levels in the range of hundreds. This could be due to a different nature of PM, the first peak reflecting a stronger anthropogenic and the second - weaker non-anthropogenic particles' effect. The current analysis is focused at the biphasic pattern on the association between PM levels with BG and asthma exacerbations. Pollutants were assessed by local monitoring stations and a satellitebased model. Local weekends/holidays were used to define nonanthropogenic levels of pollutants featured by lower Nitrogen Dioxide, the proxy for anthropogeneity. The association of PM10 with health outcomes within 24-48h lag was explored using spline functions of generalized additive models. Analysis of 546,420 BG tests (43,569 subjects) showed an almost linear association of PM10 with asthma with BG during the days with anthropogenic activity and no trend on other days. Analysis of asthmatic exacerbations within 1576 children showed no heterogeneity in association with PM10 by anthropogeneity levels, possibly indicating a mechanical impact on alveolar as the main trigger for exacerbations rather than PM10 chemical composition.

Temperature and preeclampsia: Epidemiological evidence that perturbation in maternal heat homeostasis affects pregnancy outcome.

INTRODUCTION: This study aims to determine the association between temperature and preeclampsia and whether it is affected by seasonality and rural/urban lifestyle. METHODS: This cohort study included women who delivered at our medical center from 2004 to 2013 (31,101 women, 64,566 deliveries). Temperature values were obtained from a spatiotemporally resolved estimation model performing predictions at a 1×1km spatial resolution. In "Warm" pregnancies >50% of gestation occurred during the spring-summer period. In cold pregnancies >50% of gestation occurred during the fall and winter. Generalized estimating equation multivariable models were used to estimate the association between temperature and incidence of preeclampsia. RESULTS: 1) The incidence of preeclampsia in at least one pregnancy was 7% (2173/64,566); 2) during "warm" pregnancies, an elevation of one IQR of the average temperature in the 1st or the 3rd trimesters was associated with an increased risk to develop preeclampsia [patients with Jewish ethnicity: 1st trimester: relative risk (RR) of 2.38(95%CI 1.50; 3.80), 3rd trimester 1.94(95%CI 1.34;2.81); Bedouins: 1st trimester: RR = 2.91(95%CI 1.98;4.28), 3rd trimester: RR = 2.37(95%CI 1.75;3.20)]; 3) In "cold" pregnancies, an elevation of one IQR of average temperature was associated with a lower risk to develop preeclampsia among patients with Bedouin-Arab ethnicity RR = 0.68 (95% CI 0.49-0.94) for 1st trimester and RR = 0.62 (95% CI 0.44-0.87) for 3rd trimester. CONCLUSIONS: 1) Elevated averaged temperature during the 1st or 3rd trimesters in "warm" pregnancies confer an increased risk for the development of preeclampsia, especially in nomadic patients; 2) Of interest, during cold pregnancies, elevated averaged temperature was associated with a lower risk to develop preeclampsia for nomadic patients. 3) These findings suggest temperature might be associated with perturbations in maternal heat homeostasis resulting in reallocation of energy resources and their availability to the fetus that may increase the risk for preeclampsia. This observation is especially relevant in the context of global warming and its effects on maternal/fetal reproductive health.

Life prevalence of upper respiratory tract diseases and asthma among children residing in rural area near a regional industrial park: cross-sectional study.

INTRODUCTION: The study described was initiated by the Israel Ministry of Health as an effort to respond to and deal with public concern about possible health disorders related to odorous emissions (composed of a great many of organic and inorganic chemicals) from the regional industrial park (IP) in the Negev, southern Israel. Previous ecological studies found that adverse health effects in the Negev Bedouin population were associated with residential proximity to the IP. The objective of the current study was to investigate a hypothesis concerning the link between the IP proximity and life prevalence (LP) of upper respiratory tract chronic diseases (URTCD) and asthma in children aged 0-14 years living in rural Negev, Israel, in small agricultural communities. METHODS: The cross-sectional study was conducted in 7 localities simultaneously during 2002. The following indirect exposure indicators were used: (1) distance (less than 20 km/ more than 20 km) from the IP ('distance'); (2) presence (yes/no) of the dominant wind direction being from the IP toward a child's locality ('wind direction'); and (3) the child's mother having made odour complaints (yes/no) related to the IP ('odour complaints'). A 20 km cut-off point was used for 'distance' dichotomization as derived from the maximum range of 'odour complaints'. This gave 3 proximal and 4 distant localities, and division of these by the 'wind direction' gave one versus two localities. The study population consisted of 550 children born in the localities. Medical diagnoses were collected from local clinic records. The following were included in the interviewer-administered questionnaire for a child's parents: (1) demography (the child's birth date, gender, mother being married or not, parental origin and education, number of siblings); (2) the child's birth history (pregnancy and delivery) and breast-feeding duration; (3) the child's parental respiratory health; and (4) environmental factors (parental smoking and occupational hazardous exposure, domestic use of pesticides, domestic animals, outdoor odour related to the IP emissions). For statistical analysis, Pearson's chi(2), t-tests and multivariate logistic regressions were used, as well as adjusted odds ratios (OR) within a 95% confidence interval. RESULTS: The multivariate analysis showed that increased LP of URTCD in children of proximal localities was statistically significant when associated with odour complaints (OR = 3.76 [1.16, 12.23]). In proximal localities, LP of URTCD was higher (at borderline level statistical insignificance p = 0.06) than in distant localities (OR = 2.31 [0.96, 5.55]). The following factors were found to be related to the excess of the LP of URTCD: (1) father's lower education (by distance: OR = 2.62 [1.23, 5.57]; by wind direction: OR = 4.07 [1.65, 10.03]); (2) in-vitro fertilization (by distance: OR = 3.03 [1.17, 7.87]; by wind direction: OR = 4.34 [1.48, 12.72]). In proximal localities, the increase in asthma LP was associated with: (1) wind direction (OR = 1.95 [1.01, 3.76]); (2) a child's male gender (OR = 2.95 [1.48, 5.87]); and (3) a child's mother's having had an acute infectious disease during pregnancy (OR = 4.84 [1.33, 17.63]). CONCLUSIONS: An increased LP of chronic respiratory morbidity among children living in small agricultural localities in the Negev was found to be associated with indirect measurements of exposure (distance, wind direction and odour complaints) to IP emissions. These results, in conjunction with previously reported findings in the Negev Bedouin population, indicate a need for environmental protection measures, and monitoring of air pollution and the health of the rural population.

Major congenital malformations and residential proximity to a regional industrial park including a national toxic waste site: an ecological study.

BACKGROUND: Public concern about exposure to emissions from the regional industrial park (IP), including 17 chemical plants and the national industrial toxic waste site, initiated this study of the possible association between major congenital malformations (MCM) and residence near the IP in Israel's Southern District. METHODS: The study was conducted during the period 1995-2000 and included 63,850 deliveries. Data on deliveries and MCM detected at births were obtained from the regional medical center, and stratified by ethnicity and type of locality. As exposure indicator we used distance categories (proximal and distant) and predominant wind direction from the IP. Distance stratification was based on the geographical distribution of the localities and complaints about the odor related to IP emissions. Based on these complaints, localities up to 20 km from the IP were considered proximal to the IP. RESULTS: Average rates of MCM were 5.0% and 4.1% for Bedouin and Jewish newborns, respectively. The rate of MCM for Bedouin from proximal localities was significantly greater compared with distant localities (5.6% vs. 4.8%; RR = 1.17 with 95% CI: 1.04-1.29). In the proximal Bedouin permanent localities, the MCM rate reached 8.2 %, which was significantly higher than in distant areas (RR = 1.63, 95% CI: 1.39-1.80). Significant risk increase of central nervous system MCM was found in these localities, compared to distant ones (RR = 2.27, 95% CI: 1.44-3.60). Among newborns from the traditional tribal settlements, proximity to the IP was associated with increased rates of the following MCM: 1) all combined, 2) those associated with chromosomal abnormalities, and 3) those defined as "others unclassified MCM." Comparison of autosomal recessive disease rates by proximity to the IP in Bedouin newborns indicates that the observed increased risk of MCM is not explained by consanguineous marriages. The rates of MCM in the Jewish population were similar among "exposed" and "unexposed" inhabitants. CONCLUSION: Residential proximity to the IP is associated with increased rates of MCM among Arab-Beduin but not in Jewish populations. These observations indicate the need for public health protection of a vulnerable society in transition, although the relative importance of chemical exposure and health care utilization requires further study.

Accuracy and cost-benefit of pooled versus singleton screening blood donations for anti-HIV: impact on different blood bank set-ups.

This study evaluates the accuracy and cost-benefit of implementing a pooled screening procedure in blood banks in general and especially in developing countries. The sensitivity of pooled testing was found to be relatively high, with the lowest levels estimated at about 98% for pools consisting of three, six, and 12 samples. Screening in pools of up to 12 samples is expected to be economically beneficial in countries with HIV prevalence rates of 8-10%, which cannot afford the cost of care for an HIV-infected patient.

Relationship of ambient air pollutants and hazardous household factors with birth weight among Bedouin-Arabs.

BACKGROUND: Air pollution and meteorology exposures during pregnancy have been suggested to be associated with Birth Weight (BW). Yet, the individual medical background and close household environment is rarely addressed. We aimed to evaluate the independent association of BW with meteorological and air pollution exposures during pregnancy, in addition to individual, parental and household risk factors, among the Bedouin-Arab population in Southern Israel; a semi nomadic population, featured by low socio-economic levels and poor housing and household environment. METHODS: In a retrospective cohort study we enrolled pregnant women upon their arrival in the local hospital for delivery during December 2011-April 2013. We interviewed the women and collected data on socio-demographic characteristics, medical history and household environmental hazards. Air pollution (NO2, SO2, CO, Ozone and Particulate Matter <2.5 µ and 10 µ in diameter) and meteorological data (temperature, relative humidity), retrieved from 13 monitoring sites, were linked to each woman based on the proximity of her residential address. RESULTS: A total of 959 women were eligible for the study, half of them resided in temporary tribal localities. Ozone IQR elevation in the 3rd trimester was associated with 0.119 gr decrease in BW (95%CI -0.127 gr; -0.112 gr); temperature IQR elevation in the 3rd trimester was associated with 0.002 gr (95%CI -0.004 gr; -0.001 gr) decrease in BW. Waste in the house surroundings was associated with a decrease of 117.27 gr in BW (95%CI -209.19 gr; -25.34 gr). CONCLUSION: Although exposure to high levels of temperature and O3 were associated with lower BW, the contribution of poor household environment indicators to BW reduction was substantially higher.

Can cell proliferation of umbilical cord blood cells reflect environmental exposures?

Environmental hazards were shown to have an impact on cell proliferation (CP). We investigated CP of lymphocytes in umbilical cord blood in relation to prenatal environmental exposures in a sample of 346 Arab-Bedouin women giving birth in a local hospital. Information on subjects' addresses at pregnancy, potential household exposures and demographical status was collected in an interview during hospitalization. This population is usually featured by high rates of neonatal morbidity and multiple environmental exposures, originating from the local industrial park (IP), household hazards and frequent male smoking. A geometric mean CP ratio 2.17 (2.06; 2.29), and was high in women residing in a direction of prevailing winds from the local IP (p value = 0.094) and who gave birth during fall-winter season (p value = 0.024). Women complaining on disturbing exposure to noise had lower CP (p value = 0.015), compared to other women. CP was not indicative of neonatal morbidity. However, our findings suggest that CP of umbilical cord might be modified by environmental exposures. A long-term follow-up of the children is required to assess their developmental outcomes.

Exposure to metals and congenital anomalies: a biomonitoring study of pregnant Bedouin-Arab women.

BACKGROUND: The Bedouin-Arab population in Israel comprises a low socio-economic society in transition. Smoking among males and consanguineous marriages are frequent. A previous study showed elevated rates of major malformations within groups from this population residing near an industrial park, where high ambient values of arsenic (As) and nickel (Ni) were detected, compared to groups living in remote localities. OBJECTIVES: We estimated the extent of exposure to metals in pregnant Bedouin-Arab women in relation to congenital malformations. METHODS: We collected maternal urine samples from 140 Bedouin women who gave birth in a local hospital. Patient medical history, type of marriage (consanguineous or non-consanguineous), and parental exposure history were collected by interview and medical records. RESULTS: Aluminum (Al) was detected in 37 women (26.4%), cadmium (Cd) in 2 (1.4%), As in 10 (7.1%), and Ni in 1 woman (0.7%). The detected rate of Cd exposure was low, though more than 92% of the fathers reported smoking. Concentrations of Al were higher for women residing within 10 km of the local industrial park (Prevalence Ratio (PR)=1.12, p-value=0.012) or who reported using a wood burning stove (PR=1.37, p-value=0.011) and cooking over an open fire (PR=1.16, p-value=0.076). Exposure to Al was adversely associated with minor anomalies (OR=3.8, p-value=0.046) after adjusting for history of abortions (OR=6.1, p-value=0.007). Fetuses prenatally exposed to As were born prematurely (p-value=0.001) and at lower weights (pv=0.023). CONCLUSIONS: The study population of pregnant women is exposed to high levels of metals mainly of household origin. Our findings may be generalized to similar populations in developing countries.

Retinol concentration in maternal and cord serum: its relation to birth weight in healthy mother-infant pairs.

BACKGROUND: Vitamin A is an essential micronutrient for the development and growth of the fetus. The objective of this study was to identify a possible association between low serum retinol and birth weight in healthy mother-infant pairs in Southern Israel. A secondary objective was to examine ethnic differences in maternal and cord serum retinol. METHODS: Serum retinol was measured at delivery from pairs of healthy mothers and healthy mature newborns. RESULTS: Of the 313 mother-infant pairs studied, 56% were Jews and 44% Bedouins. The proportion of infants with birth weight of 2500-2999 g was greater among mothers with lower serum retinol (<0.7 micromol/l) compared to mothers with normal serum retinol (> or =0.7 micromol/l) (p<0.001). Cord retinol <0.7 micromol/l was more frequent in infants with birth weight 2500-2990 g compared to infants with birth weight > or =3000 g (p=0.006). Using a split model and stepwise multiple regression analysis, infant's birth weight was significantly influenced by cord retinol concentration in infants born to mothers with low serum retinol; gestational age and cord retinol alone explained 27% of the variability of birth weight in this group. A higher proportion of Bedouin than Jewish infants had serum retinol <0.7 and <0.35 micromol/l (both p<0.001). CONCLUSION: Low cord and maternal serum retinol may reflect poor vitamin A status of the newborn and the mother, which in turn may affect fetal growth.

Mortality in the bedouin population and proximity to a regional industrial complex.

BACKGROUND: The study was initiated by public concern about exposure to an industrial park (IP) emission. The study examined whether mortality in the Bedouin population in the southern part of Israel is associated with the residential distance to the IP. MATERIAL AND METHODS: Ecological study during 1995-2001 included the entire Bedouin population. Mortality data was obtained from the Central Bureau of Statistics. As an indirect measurement of exposure we used residential distance to the IP (with 20 km radius as a cut-of-point) based on residents' complaints about odor related to the IP. Differences in mortality rates by distance were assessed by the Mantel-Haenszel relative risk (M-H RR) within the 95% CI. The country Arab population served as a reference for calculation of the age-adjusted standardized mortality ratio (SMR). RESULTS: Increased mortality rates due to symptoms/ill-defined conditions and non-external causes were observed in the Bedouin population of both sexes, residing up to 20 km from the IP, compared to those living in more remote areas. Corresponding M-H RR (plus 95% CI) were 1.66 (1.17-2.36), 1.24 (1.06-1.44) in females, and 1.55 (1.15-2.10), 1.32 (1.15-1.52) in males. CONCLUSIONS: The study results suggest an association between residential proximity to the regional IP and increased mortality rates in the Negev Bedouin population. These findings have been accepted by the authorities as an issue for community health protection.

Perinatal mortality and residential proximity to an industrial park.

The authors' objective was to determine whether residential proximity to an industrial park (IP) is associated with increased perinatal mortality (PM). This semiecological study included 63,850 delivered births with 840 cases of PM (1995-2000). The authors categorized the study populations by ethnicity (ie, Bedouin and Jewish) and type of locality. Residential distance from the IP served as a surrogate indicator of exposure. Among Bedouin newborns, proximity to the IP was associated with increased PM rates (relative risk = 1.45; 95% confidence interval = 1.22-1.72). The excess in PM was not related to maternal or newborn physical characteristics that the authors observed. The risk of PM and its components in the Jewish localities was not associated with IP proximity. The association between residential proximity to the IP and excess in PM among only Bedouin newborns may be related to vulnerability caused by the nomadic nature of the society.

Evaluation of pooled screening for anti-HCV in two blood services set-ups.

OBJECTIVE: Screening blood donations for anti-HCV is only partially performed in many developing countries due to the relatively high costs of testing. The screening expenditures can be reduced by testing donations in pools. This study evaluates the accuracy and feasibility of pooled screening procedure for anti-HCV in blood banks in Israel and the Palestinian Authority. METHODS: The sensitivity and specificity of tests performed on pool sizes of 6-24 samples were compared to singleton immunoassay testing. All negative samples and those positive for anti-HCV were obtained from the routine work of Magen David Adom Blood Services in Israel and Shifa Hospital blood bank in Palestinian Authority. The experiments were run in parallel with different technologies. RESULTS: The sensitivity of pooled-testing for anti-HCV by Magen David Adom was 94-97% for verified samples. In the Shifa Hospital, the sensitivity was estimated as 96-97% for non-verified samples. Cost-analysis showed benefits up to $2 per donation screened for anti-HCV in Shifa Hospital. CONCLUSIONS: We recommend using manually created pools of up to 6 samples when testing for anti-HCV, but at the cost of 3% loss in sensitivity. Pooling can be considered, in countries which do not perform routine screening, due to their limited economic resources.

Use of seroconversion panels to estimate delay in detection of anti-human immunodeficiency virus antibodies by enzyme-linked immunosorbent assay of pooled compared to singleton serum samples.

The transfusion of unsafe blood worldwide accounts for 5 to 15% of new human immunodeficiency virus (HIV) infections, most of which occur in sub-Saharan Africa. While developed countries now apply PCR testing of pooled samples, some developing countries still do not have universal screening policies. More efficient low-cost procedures for the screening of pooled samples have the potential to encourage mass screening efforts in resource-poor settings. The aim of this study was to estimate the delay in the detection of HIV antibodies in pooled serum samples compared to that in singleton serum samples by enzyme-linked immunosorbent assay (ELISA) and to evaluate the risk of transfusion-transmitted HIV infection during the window period. Serial blood samples obtained from five HIV seroconversion panels were mixed with HIV-seronegative blood samples to create pools of 6, 12, 16, 24, 32, and 48 samples. The delay in detection of the first anti-HIV antibody-positive sample in tests with pooled samples was calculated for each pool size and compared to that obtained by testing of singleton samples and statistically evaluated by a robust log-linear regression analysis. The risk of a false-negative (FN) result caused by dilution was estimated by use of the incidence risk/window period model. The additional risk of transmission related to ELISA screening of pooled samples for HIV did not exceed 9% of the current risk of an FN result (estimated to be 1/1,067,000). The countries with virus prevalence rates in donors of less than 15% are expected to save up to 30% in the number of tests. ELISA screening of pooled samples could be considered in settings where the testing of blood supplies for HIV is not routinely done.

Accuracy of hepatitis C virus core antigen testing in pools among seroconverters.

BACKGROUND: Screening blood units for hepatitis C virus (HCV) with nucleic acid testing (NAT) reduces the risk associated with the long "window period" (8-9 weeks) after HCV infection. The feasibility of adding the HCV core antigen assay in pools to the existing anti-HCV individual screening was examined as an alternative of NAT, for early detection of HCV. STUDY DESIGN AND METHODS: Eighteen HCV seroconversion panels were tested for HCV antibodies, HCV antigen, and HCV RNA. Each sample was tested for HCV antigen individually and in pools of 3, 6, and 12. Statistical analyses included estimation of time until detection of the first positive HCV antigen bleed in each pool size, with a locally weighted regression (LOWESS) model. Sensitivity was calculated compared to NAT. RESULTS: Detection of HCV antigen in individual samples and in pools of 3 and 6 significantly preceded the detection of antibodies by 63, 53, and 46 days, respectively. Although the sensitivity of the HCV antigen test decreased with the increase in pool size, the estimated overall sensitivity of the "two-stage" antigen and antibody screening (where NAT of individual samples was the gold standard) was not significantly different between individual and the different pool sizes. CONCLUSION: Screening for HCV antigen in pools of 6 can be considered an efficient and easier-to-implement alternative to the costly NAT for identifying blood donors in the seroconversion period. It may offer a cost-effective approach in resource utilization in poor countries, that, after the implementation of HCV antibody testing, want to further improve blood safety.