Validation of the Lead Care II System in Cape vultures (Gyps coprotheres) in comparison to ICP-MS using pure standards.

Lead toxicosis remains a concern in raptors, especially following feeding on carcasses sourced from hunting. Rapid diagnosis of lead exposure and easy field monitoring is desirable. The LeadCareII analytical system, validated for rapid diagnoses of lead toxicity in humans, has been described as a useful evaluation system in various species. For this study we attempt to validate the LeadCareII system in the Cape Vulture (CV) (Gyps coprotheres). Blood samples from CV housed under captive conditions and low background lead exposure, were pooled and spiked with known concentrations of a lead standard (0-60 µg/dL). Samples were analyzed by the LeadCareII system and by ICP-MS. The final results showed that despite good linearity the LeadCareII system underestimated lead concentrations by up to 50 %. While the results can be corrected by the derived equation, this is not supported due to the large underestimations evident. The reason for the underestimation is presently unknown.

Leadcare® II Comparison with Graphite Furnace Atomic Absorption Spectrophotometry for Blood Lead Measurement in Peruvian Highlands.

Peru is one of the countries with the highest lead contamination in the world. Biological monitoring has limitations due to the shortage of laboratories with validated methodologies for the measurement of blood lead, and it is necessary to use alternative methods for its measurement in high-altitude cities. We aimed to compare the blood lead levels (BLL) measured by the LeadCare II (LC) method and Graphite Furnace Atomic Absorption Spectrometry (GF-AAS). We measured the BLL of 108 children from the city of La Oroya. The mean and median BLL for GF-AAS were 10.77 ± 4.18 and 10.44 µg/dL, respectively; for the LC method, the mean was 11.71 ± 4.28 and the median was 11.60 µg/dL. We found a positive linear correlation (Rho = 0.923) between both methods. Notwithstanding, the Wilcoxon test suggests a significant difference between both methods (ρ = 0.000). In addition, the Bland-Altman analysis indicates that there is a positive bias (0.94) in the LC method, and this method tends to overestimate the BLL. Likewise, we performed a generalized linear model to evaluate the influence of age and hemoglobin on BLL. We found that age and hemoglobin had a significant influence on BLL measured by the LC method. Finally, we used two non-parametric linear regression methods (Deming and Passing-Bablok regression) to compare the LC method with the GF-AAS. We found that these methods differ by at least a constant amount, and there would be a proportional difference between both. Although in general there is a positive linear correlation, the results of both methods differ significantly. Therefore, its use in cities located at high altitudes (higher than 2440 m.a.s.l.) would not be recommended.

Post-mortem blood lead analysis; a comparison between LeadCare II and graphite furnace atomic absorption spectrometry analysis results.

PURPOSE: A comparison of the LeadCare II (LCII) point-of-care (POC) device with the gold standard graphite furnace atomic absorption spectroscopy (GFAAS) device was done in the context of post-mortem blood lead concentrations to determine comparability for screening value. METHODS: Consecutive autopsy cases from March 2018 to March 2019 were examined by the forensic medicine center. Blood samples with lead concentrations <10 µg dL-1 by LCII analysis were excluded from GFAAS analysis. Samples were collected from femoral veins or cardiac chambers. Bland-Altman analysis was conducted to evaluate the agreement between both GFAAS and LCII lead values. Linear regression modeling was performed to predict GFAAS results based on LCII results. Five-hundred post-mortem blood samples were evaluated by LCII for blood lead. For 46 cases with LCII blood lead level (BLL) values more than 10 µg dL-1, further analysis was performed by GFAAS. RESULTS: Mean difference of BLL between the two methods was 5.92 µg dL-1 (SD = 7.51; range: -14 to 23.7). GFAAS BLL values were significantly higher than LCII values (p = 0.029). Moreover, substance-user samples had significantly higher GFAAS BLLs (p = 0.006; mean difference = 11.62 µg dL-1). A significant regression equation was found (F [1, 44] = 108.44, p < 0.001, with an R2 of 0.711). Based on Bland-Altman plot averages for both predicted GFAAS BLL and measured GFASS BLL showed a mean difference was 0.014 (SD = 7.51; range: -17.9 to 20). CONCLUSION: In conclusion, on post-mortem BLL samples, LCII and GFAAS show favorable correlation. LCII can be used as a screening technique for post-mortem blood lead analysis.

Assessment of LeadCare® II analysis for testing of a wide range of blood lead levels in comparison with ICP-MS analysis.

The LeadCare® testing system, which utilizes anodic stripping voltammetry (ASV) methodology, has been widely used worldwide for cost-effective blood lead level (BLL) screening. However, some concerns have recently been issued regarding inaccurate results obtained using LeadCare®. Hence, we aimed to evaluate the accuracy of BLL measured by LeadCare® II (BLLLC) by comparison with ICP-MS (BLLIM) by the Passing-Bablok regression, Deming regression, and Bland-Altman analyses by using 994 venous blood samples. BLLLC ranged from 3.3 to 162.3 µg/dL, while BLLIM ranged from 0.8 to 154.8 µg/dL. Although BLLLC and BLLIM exhibited a strong and positive correlation, BLLLC values were generally greater than BLLIM values, indicative of the overestimation of the LeadCare® analysis. A large positive bias of 19.15 ± 8.26 µg/dL and 29.25 ± 14.04 µg/dL for BLLLC compared with BLLIM were recorded in the BLLLC range of 45.0-64.9 µg/dL and for ≥65.0 µg/dL, respectively. In contrast, a bias of ≤0.3 µg/dL was observed at a BLLLC of less than 10.0 µg/dL. Blood copper, cadmium, and iron levels did not exhibit an effect on the bias of BLLLC, indicative of the minimal potential interferences of the metals; these interferences are a cause for concern with the ASV method. In conclusion, LeadCare® analysis is thought to be a good tool for screening purposes at a lower BLL around the reference level of 5 µg/dL in the initial stage; however, conversion or retesting using a laboratory analyzer is recommended at a higher BLL for appropriate clinical evaluation and research.

Current trends of blood lead levels, distribution patterns and exposure variations among household members in Kabwe, Zambia.

Childhood lead (Pb) poisoning has devastating effects on neurodevelopment and causes overt clinical signs including convulsions and coma. Health effects including hypertension and various reproductive problems have been reported in adults. Historical Pb mining in Zambia's Kabwe town left a legacy of environmental pollution and childhood Pb poisoning. The current study aimed at establishing the extent of Pb poisoning and exposure differences among family members in Kabwe as well as determining populations at risk and identify children eligible for chelation therapy. Blood samples were collected in July and August 2017 from 1190 household members and Pb was measured using a portable LeadCare-II analyser. Participants included 291 younger children (3-months to 3-years-old), 271 older children (4-9-years-old), 412 mothers and 216 fathers from 13 townships with diverse levels of Pb contamination. The Blood Lead Levels (BLL) ranged from 1.65 to 162  µg/dL, with residents from Kasanda (mean 45.7  µg/dL) recording the highest BLL while Hamududu residents recorded the lowest (mean 3.3  µg/dL). Of the total number of children sampled (n = 562), 23% exceeded the 45  µg/dL, the threshold required for chelation therapy. A few children (5) exceeded the 100  µg/dL whereas none of the parents exceeded the 100  µg/dL value. Children had higher BLL than parents, with peak BLL-recorded at the age of 2-years-old. Lead exposure differences in Kabwe were attributed to distance and direction from the mine, with younger children at highest risk. Exposure levels in parents were equally alarming. For prompt diagnosis and treatment, a portable point-of-care devise such as a LeadCare-II would be preferable in Kabwe.

Evaluation of LeadCare Ultra® as an initial screen for elevated blood lead levels.

OBJECTIVE: The LeadCare Ultra® (LCU) was compared to inductively coupled plasma mass spectrometry ICP-MS for use as a screening test for elevated blood lead levels (BLLs) in capillary samples from children. METHODS: During the validation, method comparisons between LCU and ICP-MS were analyzed to determine the bias above, near, and below the BLL cut-off of 5 µg/dL. Additionally, capillary samples that screened positive by LCU (above the 5 µg/dL cut-off) were compared to venous samples analyzed by ICP-MS for confirmatory testing. RESULTS: LCU had a positive bias (1.7 µg/dL) below the cut-off of BLL <5 µg/dL, no bias near the cut-off from BLL 5-10 µg/dL, and a negative bias (-0.8 µg/dL) for BLL >10 µg/dL compared to ICP-MS. Of the 59 capillary samples that screened positive by LCU between May of 2017 to April of 2018, 19 were confirmed positive by ICP-MS, 30 were confirmed negative by ICP-MS, and 10 did not have a confirmed result. CONCLUSION: The LCU assay is an acceptable screen for capillary samples with the BLL cut-off of 5 µg/dL.

A Pilot Study of Children's Blood Lead Levels in Mount Isa, Queensland.

Mount Isa, Queensland, is one of three Australian cities with significant lead emissions due to nonferrous mining and smelting. Unlike the two other cities with lead mines or smelters, Mount Isa currently has no system of annual, systematic, community-wide blood lead level testing; and testing rates among Indigenous children are low. In previous screenings, this group of children has been shown to have higher average blood lead levels than non-Indigenous children. The first aim of this study was to assess whether parents and children would participate in less invasive, rapid point-of-care capillary testing. The second aim was to measure blood lead levels among a range of children that roughly reflected the percentage of the Indigenous/non-Indigenous population. This pilot study is based on a convenience sample of children between the ages of 12 and 83 months who were recruited to participate by staff at a Children and Family Centre. Over three half-days, 30 children were tested using capillary blood samples and the LeadCare II Point-of-Care testing system. Rapid point-of-care capillary testing was well tolerated by the children. Of 30 children tested, 40% (n = 12) had blood lead levels ≥5 µg/dL and 10% had levels ≥10 µg/dL. The highest blood lead level measured was 17.3 µg/dL. The percentage of children with blood lead levels ≥5 µg/dL was higher among Indigenous children compared to non-Indigenous (64.2% compared to 18.8%) as was the geometric mean level (6.5 (95% CI, 4.7, 9.2) versus 2.4 (95% CI, 1.8, 3.1)), a statistically significant difference. Though based on a small convenience sample, this study identified 12 children (40%) of the sample with blood lead levels ≥5 µg/dL. Due to historical and ongoing heavy metal emissions from mining and smelting in Mount Isa, we recommend a multi-component program of universal blood lead level testing, culturally appropriate follow-up and intervention for children who are identified with blood lead levels ≥5 µg/dL. We further recommend focused outreach and assistance to the Indigenous community, and further control of emissions and remediation of existing environmental lead contamination in children's play and residential areas.

A rapid postmortem screening test for lead toxicosis in common loons (Gavia immer) and bald eagles (Haliaeetus leucocephalus).

In live animals, lead poisoning can be diagnosed by analyzing blood samples. For postmortem testing, blood samples are not available and analysis of liver or kidney is often used for diagnosis. Liver and kidney analysis is relatively expensive and results might not be quickly available. We examined an inexpensive, rapid method to screen animals for lead toxicosis postmortem by testing the mixture of body fluids (termed "tissue fluids") that pool in the body cavity at necropsy for lead. At necropsy we collected body fluid and liver samples from Common Loon (Gavia immer) and Bald Eagle (Haliaeetus leucocephalus) carcasses and determined concentrations of lead in tissue fluid using a desk-top blood lead analyzer. Concentrations of lead in liver were determined by inductively coupled plasma mass spectroscopy. There was strong correlation between tissue fluid and liver tissue lead concentrations, and receiver-operating characteristic analysis gave an area under the curve of 0.91, indicating that postmortem measurements of lead in tissue fluids can be utilized as a screening method for lead toxicosis.