Free erythrocyte protoporphyrin (FEP) and zinc protoporphyrin (ZnP) as biological parameters for lead poisoning

1984 ◽  
Vol 53 (4) ◽  
pp. 365-377 ◽  
Author(s):  
Kohichi Harada ◽  
Hajime Miura
Keyword(s):  
Lead Poisoning ◽  
Zinc Protoporphyrin ◽  
Biological Parameters ◽  
Free Erythrocyte Protoporphyrin ◽  
Erythrocyte Protoporphyrin

scholarly journals Pitfalls in Erythrocyte Protoporphyrin Measurement for Diagnosis and Monitoring of Protoporphyrias

2015 ◽  
Vol 61 (12) ◽  
pp. 1453-1456 ◽  
Author(s):  
Eric W Gou ◽  
Manisha Balwani ◽  
D Montgomery Bissell ◽  
Joseph R Bloomer ◽  
Herbert L Bonkovsky ◽  
...  
Keyword(s):  
Lead Poisoning ◽  
Reference Interval ◽  
Laboratory Diagnosis ◽  
Reference Intervals ◽  
Zinc Protoporphyrin ◽  
Similar Increase ◽  
Erythropoietic Protoporphyria ◽  
Metal Free ◽  
Erythrocyte Protoporphyrin

Abstract BACKGROUND Laboratory diagnosis of erythropoietic protoporphyria (EPP) requires a marked increase in total erythrocyte protoporphyrin (300–5000 μg/dL erythrocytes, reference interval <80 μg/dL) and a predominance (85%–100%) of metal-free protoporphyrin [normal, mostly zinc protoporphyrin (reference intervals for the zinc protoporphyrin proportion have not been established)]; plasma porphyrins are not always increased. X-linked protoporphyria (XLP) causes a similar increase in total erythrocyte protoporphyrin with a lower fraction of metal-free protoporphyrin (50%–85% of the total). CONTENT In studying more than 180 patients with EPP and XLP, the Porphyrias Consortium found that erythrocyte protoporphyrin concentrations for some patients were much higher (4.3- to 46.7-fold) than indicated by previous reports provided by these patients. The discrepant earlier reports, which sometimes caused the diagnosis to be missed initially, were from laboratories that measure protoporphyrin only by hematofluorometry, which is intended primarily to screen for lead poisoning. However, the instrument can calculate results on the basis of assumed hematocrits and reports results as “free” and “zinc” protoporphyrin (with different reference intervals), implying separate measurements of metal-free and zinc protoporphyrin. Such misleading reports impair diagnosis and monitoring of patients with protoporphyria. SUMMARY We suggest that laboratories should prioritize testing for EPP and XLP, because accurate measurement of erythrocyte total and metal-free protoporphyrin is essential for diagnosis and monitoring of these conditions, but less important for other disorders. Terms and abbreviations used in reporting erythrocyte protoporphyrin results should be accurately defined.

Lead poisoning: Zinc protoporphyrin in blood of children from Santo Amaro da Purificação, Bahia, Brazil

1996 ◽  
Vol 72 (5) ◽  
pp. 295-298 ◽  
Author(s):  
Fernando M. Carvalho ◽  
Annibal M. S. Neto ◽  
Maria F. T. Peres ◽  
Henrique R. Gonçalves ◽  
Gustavo Cardoso Guimarães ◽  
...  
Keyword(s):  
Lead Poisoning ◽  
Zinc Protoporphyrin

Screening for Lead Poisoning in an Urban Pediatric Clinic Using Samples Obtained by Fingerstick

PEDIATRICS ◽  
1994 ◽  
Vol 94 (2) ◽  
pp. 174-179
Author(s):  
David J. Schonfeld ◽  
Mark R. Cullen ◽  
Petrie M. Rainey ◽  
Anne T. Berg ◽  
David R. Brown ◽  
...  
Keyword(s):  
Lead Poisoning ◽  
False Positive ◽  
Lead Concentration ◽  
Capillary Tube ◽  
Graphite Furnace ◽  
False Positive Rate ◽  
Screening Tests ◽  
Zinc Protoporphyrin ◽  
Pediatric Clinic ◽  
Positive Rate

Objective. To assess the false positive rate of blood (BPb) determinations on sample obtained by fingerstick from children screened in an urban clinic. Method. From a single fingerstick (N = 1573), blood was collected in a capillary tube for determining lead concentration (CPb) by graphite furnace and an additional sample was absorbed onto a filter paper for determining lead concentration (FPb) by atomic absorption spectrophotometry with Delves cup. Zinc protoporphyrin (ZPP) was measured immediately and a confirmatory venous lead (VPb) specimen was obtained at the same visit if the ZPP was ≥35 µg/dL (0.6 µmol/L); children with either a CPb or FPb ≥15 µg/dL (0.7 µmol/L) were later recalled for determining VPb. Results. For the 172 children who had a VPb on the same day as the screening tests, the false positive rates (95% confidence intervals) at a lead threshold of 15 µg/dL (0.7 µmol/L) were: CPb, 13.5% (6.7-20.3); FPb, 19.1% (11.8-26.4). Analyses using all 679 screens with a paired venous specimen (mean delay between screen and venous testing = 30 days) yielded much higher false positive rates (CPb, 31.3%; FPb, 46.0%). Conclusions. Screening for lead poisoning is feasible within an urban pediatric clinic by direct measurement of lead concentration in blood samples obtained by fingerstick. The false positive rate that can be obtained is acceptable given the precision of measuring BPb concentration. Practitioners using a staged screening protocol may incorrectly attribute a higher false positive rate to the screening tests, when much of the error may be due to the temporal variability of BPb resulting from both biologic variability in BPb concentration and intermittent exposures.

Too Much Lead, Too Little Iron

PEDIATRICS ◽  
1988 ◽  
Vol 82 (3) ◽  
pp. 395-395
Author(s):  
MARGARET CLARK
Keyword(s):  
Public Health ◽  
Iron Deficiency ◽  
Lead Poisoning ◽  
Predictive Value ◽  
Blood Lead ◽  
Blood Lead Levels ◽  
The Public ◽  
Erythrocyte Protoporphyrin ◽  
Lead Levels

In Reply.— We appreciate the work of Carraccio et al which confirms our findings that the anemia found in children with lead poisoning results from coexistent iron deficiency. The discrepancy between the two studies concerning the predictive value of blood lead in elevations of erythrocyte protoporphyrin bears further exploration. What is striking, however, is that in both series more than 50% of the variability in erythrocyte protoporphyrin remains unexplained. Now the public health focus is on detecting children with low blood lead levels—before even subtle CNS damage has occurred.

Erythrocyte Protoporphyrin IX as a Diagnostic and Therapy Evaluating Tool in Lead Poisoning

1981 ◽  
Vol 36 (1) ◽  
pp. 40-43 ◽  
Author(s):  
MIGUEL ANGEL ZÚÑIGA-CHARLES ◽  
J. DIEGO GONZÁLEZ-RAMÍREZ ◽  
GILBERTO MOLINA-BALLESTEROS
Keyword(s):  
Lead Poisoning ◽  
Protoporphyrin Ix ◽  
Erythrocyte Protoporphyrin

Normative Data of Hemoglobin Concentration and Free Erythrocyte Protoporphyrin in a Private Pediatric Practice

1986 ◽  
Vol 25 (4) ◽  
pp. 206-208 ◽  
Author(s):  
John T. Benjamin ◽  
Michael D. Dickens ◽  
Raymond F. Ford ◽  
Charles H. Gleason ◽  
Vito A. Perriello ◽  
...  
Keyword(s):  
Normative Data ◽  
Hemoglobin Concentration ◽  
Pediatric Practice ◽  
Free Erythrocyte Protoporphyrin ◽  
Erythrocyte Protoporphyrin
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