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Patrick J Parsons - One of the best experts on this subject based on the ideXlab platform.
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measurement of Erythrocyte Protoporphyrin concentration by double extraction and spectrofluorometry
Current protocols in immunology, 1999Co-Authors: Patrick J ParsonsAbstract:Quantification of the level of Erythrocyte Protoporphyrin can be used as a screening assay for lead exposure. In this method, porphyrins and heme compounds are extracted from whole blood using ethyl acetate, and porphyrins are then separated from heme by back-extraction with HCl solution. The extracted porphyrins are then quantified using a spectrofluorometer calibrated with Protoporphyrin IX standard solutions.
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evaluation of vacutainer plus low lead tubes for blood lead and Erythrocyte Protoporphyrin testing
Clinical Chemistry, 1999Co-Authors: Debra Eserniojenssen, Valerie Bush, Patrick J ParsonsAbstract:Lead poisoning is an important preventable environmental health problem. Blood lead concentrations as low as 100 μg/L (0.48 μmol/L) in whole blood have been shown to affect children’s neuropsychologic or cognitive performance adversely (1)(2)(3). In view of this, in 1991 the Centers for Disease Control and Prevention (CDC) lowered the concentration of lead in blood considered safe from 250 to 100 μg/L (from 1.21 to 0.48 μmol/L) (4). This lowered threshold has been reaffirmed by the CDC in their 1997 document on screening children for lead exposure (5). Before 1991, Erythrocyte Protoporphyrin (EP) was the standard test for screening children for lead poisoning; however, it was subsequently found to be an insensitive predictor of blood lead concentrations above the lower threshold (6). However, serial EP measurements, paired with matching blood lead measurements, are still useful in managing children with lead poisoning. In the absence of additional exposure of the child to lead, the EP concentration will continue to decrease at a faster rate than is reflected by the blood lead concentration as lead reequilibrates among blood, soft tissue, and bone stores. Another recommendation in the 1991 CDC statement was to screen all children 6 months to 6 years of age for lead poisoning, using a direct blood lead measurement. Venous blood is preferred for blood lead measurement because capillary measurements may be falsely increased by skin contamination with lead. The issue …
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observational study of Erythrocyte Protoporphyrin screening test for detecting low lead exposure in children impact of lowering the blood lead action threshold
Clinical Chemistry, 1991Co-Authors: Patrick J Parsons, Andrew A Reilly, Azmat HussainAbstract:We examined a retrospective sample of 1800 children on whom both Erythrocyte Protoporphyrin (EP) and blood lead (BPb) measurements were taken. The primary objective was to ascertain whether EP is a cost-effective screening test for low but increased BPb concentrations and to establish the optimal thresholds. The data did not provide evidence of an EP threshold at low BPb concentrations; however, the data did show a significant age effect. A subset of 500 children for whom both EP and hematocrit data were available showed no correlation between those variables. Age-specific operating characteristic curves, total error, and cost analyses are presented. The latter sets bounds on the relative cost of EP testing, above which only BPb determination should be performed. The implications of these findings are discussed in light of impending changes in U.S. federal guidelines for preventing lead poisoning in young children.
Bernard J Brabin - One of the best experts on this subject based on the ideXlab platform.
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zinc Erythrocyte Protoporphyrin as marker of malaria risk in pregnancy a retrospective cross sectional and longitudinal study
Malaria Journal, 2012Co-Authors: Edward Senga, Gibby Koshy, Bernard J BrabinAbstract:Background: The effects of iron interventions and host iron status on infection risk have been a recurrent clinical concern, although there has been little research on this interaction in pregnant women. Methods: Cross-sectional and longitudinal analyses were undertaken to determine the association of whole blood zinc Erythrocyte Protoporphyrin (ZPP) with malaria parasitaemia in pregnant women attending antenatal and delivery care at Montfort and Chikwawa Hospitals, Shire Valley, Malawi. Prevalence of antenatal, delivery and placental malaria was assessed in relation to maternal ZPP levels. The main outcome measures were prevalence of peripheral and placental Plasmodium falciparum parasitaemia and odds ratios of malaria risk. Results: A total of 4,103 women were evaluated at first antenatal visit, of whom at delivery 1327 were screened for peripheral and 1285 for placental parasitaemia. Risk of malaria at delivery (peripheral or placental) was higher in primigravidae (p<0.001), and lower (peripheral) with use of intermittent preventive anti-malarials during pregnancy (p<0.001). HIV infection was associated with increased malaria parasitaemia (p<0.02, peripheral or placental). Parasitaemia prevalence was lower in women with normal ZPP levels compared to those with raised concentrations at both first antenatal visit (all gravidae, p=0.048, and at delivery (all gravidae, p<0.001; primigravidae, p=0.056). Between first antenatal visit and delivery women who transitioned from raised (at first antenatal visit) to normal ZPP values (at delivery) had lower peripheral parasitaemia prevalence at delivery compared to those who maintained normal ZPP values at both these visits (all gravidae: 0.70, 95%CI 0.4-1.1; primigravidae: 0.3, 0.1-0.8). In regression analysis this difference was lost with inclusion of HIV infection in the model. Conclusions: Raised ZPP concentrations in pregnancy were positively associated with P. falciparum parasitaemia and were probably secondary to malaria inflammation, rather than indicating an increased malaria risk with iron deficiency. It was not possible from ZPP measurements alone to determine whether iron deficiency or repletion alters malaria susceptibility in pregnancy.
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zinc Erythrocyte Protoporphyrin as marker of malaria risk in pregnancy a retrospective cross sectional and longitudinal study
Malaria Journal, 2012Co-Authors: Edward Senga, Gibby Koshy, Bernard J BrabinAbstract:The effects of iron interventions and host iron status on infection risk have been a recurrent clinical concern, although there has been little research on this interaction in pregnant women. Cross-sectional and longitudinal analyses were undertaken to determine the association of whole blood zinc Erythrocyte Protoporphyrin (ZPP) with malaria parasitaemia in pregnant women attending antenatal and delivery care at Montfort and Chikwawa Hospitals, Shire Valley, Malawi. Prevalence of antenatal, delivery and placental malaria was assessed in relation to maternal ZPP levels. The main outcome measures were prevalence of peripheral and placental Plasmodium falciparum parasitaemia and odds ratios of malaria risk. A total of 4,103 women were evaluated at first antenatal visit, of whom at delivery 1327 were screened for peripheral and 1285 for placental parasitaemia. Risk of malaria at delivery (peripheral or placental) was higher in primigravidae (p < 0.001), and lower (peripheral) with use of intermittent preventive anti-malarials during pregnancy (p < 0.001). HIV infection was associated with increased malaria parasitaemia (p < 0.02, peripheral or placental). Parasitaemia prevalence was lower in women with normal ZPP levels compared to those with raised concentrations at both first antenatal visit (all gravidae, p = 0.048, and at delivery (all gravidae, p < 0.001; primigravidae, p = 0.056). Between first antenatal visit and delivery women who transitioned from raised (at first antenatal visit) to normal ZPP values (at delivery) had lower peripheral parasitaemia prevalence at delivery compared to those who maintained normal ZPP values at both these visits (all gravidae: 0.70, 95%CI 0.4-1.1; primigravidae: 0.3, 0.1-0.8). In regression analysis this difference was lost with inclusion of HIV infection in the model. Raised ZPP concentrations in pregnancy were positively associated with P. falciparum parasitaemia and were probably secondary to malaria inflammation, rather than indicating an increased malaria risk with iron deficiency. It was not possible from ZPP measurements alone to determine whether iron deficiency or repletion alters malaria susceptibility in pregnancy.
Richard M Krieg - One of the best experts on this subject based on the ideXlab platform.
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evaluation of the Erythrocyte Protoporphyrin test as a screen for elevated blood lead levels
The Journal of Pediatrics, 1991Co-Authors: Michael D Mcelvaine, Hyman G Orbach, Sue Binder, Lorry A Blanksma, Edmond F Maes, Richard M KriegAbstract:To study the effect of lowering the definition of an elevated blood lead level on the performance of the Erythrocyte Protoporphyrin screening test and the number of children who would require follow-up, we collected laboratory data from a screening program. The estimated sensitivity of an Erythrocyte Protoporphyrin level ≥35 μ g/dl for identifying children with elevated blood lead levels was 73% when we used 1985 Centers for Disease Control guidelines (elevated blood lead level ≥25 μ g/dl). Eight percent of the tests showed positive results. When we redefined an elevated blood lead level as ≥15 μ g/dl, the sensitivity estimate was reduced to 37% and the number of positive test results increased fourfold.
S E Adeokun - One of the best experts on this subject based on the ideXlab platform.
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reversal of aminolevulinic acid dehydratase alad inhibition and reduction of Erythrocyte Protoporphyrin levels by vitamin c in occupational lead exposure in abeokuta nigeria
Environmental Toxicology and Pharmacology, 2005Co-Authors: Oladipo Ademuyiwa, Regina Ngozi Ugbaja, David Ajiboye Ojo, A O Owoigbe, S E AdeokunAbstract:Abstract In order to investigate the toxic effects of lead during occupational exposure to this metal, the activity of aminolevulinic acid dehydratase (ALAD) and the concentrations of Erythrocyte Protoporphyrin (EPP) were determined in blood of various artisans in Abeokuta, Nigeria and these were related to blood lead levels. ALAD activity in the artisans was inhibited to varying extents. ALAD activity was inhibited to the tune of 77% in petrol station attendants while the lowest inhibition of 36% was obtained in the welders. EPP was also significantly increased in the artisans (p
Michael D Mcelvaine - One of the best experts on this subject based on the ideXlab platform.
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evaluation of the Erythrocyte Protoporphyrin test as a screen for elevated blood lead levels
The Journal of Pediatrics, 1991Co-Authors: Michael D Mcelvaine, Hyman G Orbach, Sue Binder, Lorry A Blanksma, Edmond F Maes, Richard M KriegAbstract:To study the effect of lowering the definition of an elevated blood lead level on the performance of the Erythrocyte Protoporphyrin screening test and the number of children who would require follow-up, we collected laboratory data from a screening program. The estimated sensitivity of an Erythrocyte Protoporphyrin level ≥35 μ g/dl for identifying children with elevated blood lead levels was 73% when we used 1985 Centers for Disease Control guidelines (elevated blood lead level ≥25 μ g/dl). Eight percent of the tests showed positive results. When we redefined an elevated blood lead level as ≥15 μ g/dl, the sensitivity estimate was reduced to 37% and the number of positive test results increased fourfold.