Laboratories working towards accreditation by the International Standards Organization (ISO) 15189 standard are required to demonstrate the validity of their analytical methods. The different guidelines set by various accreditation organizations make it difficult to provide objective evidence that an in-house method is fit for the intended purpose. Besides, the required performance characteristics tests and acceptance criteria are not always detailed. The laboratory must choose the most suitable validation protocol and set the acceptance criteria. Therefore, we propose a validation protocol to evaluate the performance of an in-house method. As an example, we validated the process for the detection and quantification of lead in whole blood by electrothermal absorption spectrometry. The fundamental parameters tested were, selectivity, calibration model, precision, accuracy (and uncertainty of measurement), contamination, stability of the sample, reference interval, and analytical interference. We have developed a protocol that has been applied successfully to quantify lead in whole blood by electrothermal atomic absorption spectrometry (ETAAS). In particular, our method is selective, linear, accurate, and precise, making it suitable for use in routine diagnostics.
Accreditation ; Humans ; Laboratories/standards ; Lead/*blood/standards ; Reference Standards ; *Spectrophotometry, Atomic/standards ; *Validation Studies as Topic

OBJECTIVETo develop the first grade standard analytical reference material of bovine blood lead.

METHODSAccording to standards and technology specification of primary standard reference material (JJG1006-1994), ISO 17511, and volume-effect relationship, a bovine blood lead model was developed by adding acetate lead in the feed in dose of 2-5 mg x kg(-1) x d(-1). Cow blood was collected when blood lead concentration went up to low, medium and high concentration range (90-100, 190-200, 280-300 microg/L). Blood sample was kept in tube and frozen after irradiation. The samples were tested for homogeneity and stability. ID-MS method was used to measure the lead concentration through comparison with two standard lead samples from the USA NIST SRM 955b.

RESULTSSamples of the three lead concentrations showed uniformity by single factor analysis of variance (F = 0.61, 1.64, 0.28, respectively, P > 0.05) . After 14 months monitoring, the RSD was 0.85%, 1.05% and 0.49% (t = 0.787, 1.132, 0.854, respectively, P > 0.05). The characteristic and indefinite values were 102.4 +/- 5.5; 181.2 +/- 4.0; 304.5 +/- 3.9, respectively (unit: microg/L). The reproduction of the two USA NIST SRM 955b samples further showed our methods and procedures were correct. Our sample was stabile for four days at room temperature.

CONCLUSIONThe standard reference material of bovine in our research had reached the national standard material requirements.

Animal Feed ; Animals ; Blood Chemical Analysis ; standards ; Cattle ; Lead ; blood ; Male ; Models, Animal ; Reference Standards

OBJECTIVETo describe trends of changes in blood lead levels in children aged 1 - 6 years during the time period before and after introducing lead free gasoline in Shanghai 1997 and 1999.

METHODSBlood lead levels of 1 969 children aged 1 - 6 years were determined by a sampling survey in five districts of Shanghai in August and September, 1997. Blood lead levels of the same population were re-determined by the same method from April to June in 1998 and from August to September in 1999. Filter paper blood lead test was carried out monthly using the filter paper blood lead proficiency testing program of Centers for Disease Control in the United States. The results from blood lead samples were under acceptable ranges during the study.

RESULTSThe geometric means of blood lead levels were 83 microgram/L in 1997, 80 microgram/L in 1998 and 76 microgram/L in 1999, respectively. The prevalence rates of childhood lead poisoning (blood lead level was equal or more than 100 microgram/L) were 37.8% in 1997, 25.7% in 1998 and 24.8% in 1999. The amounts of decrease on average blood lead levels in the five districts between 1997 and 1999 were 10 microgram/L, 11 microgram/L, 6 microgram/L, 4 microgram/L and 2 microgram/L, respectively.

CONCLUSIONLead poisoning is a preventable disease. The average levels of lead in young children in Shanghai decreased significantly after the introduction of lead free gasoline to Shanghai. Lead emissions from vehicles running on leaded gasoline was one of the important contributors to increase the children's blood lead levels in Shanghai. Lead poisoning is not evenly distributed among children in Shanghai, resulting in the different levels of decline.

Child, Preschool ; China ; Environmental Monitoring ; methods ; standards ; Environmental Pollutants ; blood ; Gasoline ; standards ; Humans ; Lead ; blood ; Time Factors

OBJECTIVETo use the data of occupational epidemiology to estimate the benchmark dose (BMD) of renal dysfunction induced by lead.

METHODSBlood lead was considered as an exposure biomarker, while urinary total protein (TP), urinary beta(2)-microglobulin (beta(2)-MG) and urinary N-Acetyl-beta-D-glucosaminidase (NAG) were considered as effect biomarkers reflecting the damage of renal function. The dichotomized (binary) data was used as effect endpoints. The BMD and BMD lower limit (BMDL) of blood lead were estimated at the 10% benchmark response using BMDS version 1.3.1.

RESULTSThere was an increased prevalence of hyper-TP-uria, hyper-beta(2)-MG-uria and hyper-NAG-uria with an increasing blood lead concentration. There was obviously dose-response relationship between blood lead and TP, beta(2)-MG and NAG, respectively. The BMD and BMDL of blood lead affecting renal function were estimated to be 323.6 - 754.3 microg/L and 274.2 - 541.5 microg/L. The BMDL of blood lead was ranged from low to high as NAG, TP and beta(2)-MG. The urinary NAG activity might be served as a sensitive biomarker in detecting early renal dysfunction.

CONCLUSIONIt should be feasible to use the BMD approach to set up the reference dose (RfD) and reference concentration (RfC). BMD approach might provide a new and better way for setting up the RfD/RfC.

Acetylglucosaminidase ; urine ; China ; epidemiology ; Clinical Chemistry Tests ; methods ; standards ; Humans ; Lead ; blood ; Lead Poisoning ; blood ; epidemiology ; urine ; Occupational Exposure ; analysis ; Prevalence ; Proteinuria ; urine ; beta 2-Microglobulin ; urine

BACKGROUND: Although lead neurotoxicity is a known phenomenon, it can often be missed at a primary or secondary care level especially if detailed environmental exposure history is missed. METHODS: This is an outbreak investigation where we observed 15 pediatric cases with neurologic signs and symptoms clustered in a slum area known for an unorganized artificial jewelry industry. Their clinical, biochemical, and epidemiological features were compared with 14 other children from the same region reporting with non-neurological symptoms who were considered as unmatched controls. RESULTS: Cases with neurological manifestations had a higher in-house lead smelting activity [OR 7.2 (95% CI 1.4-38.3)] as compared to controls. Toddlers below 3 years of age were more vulnerable to the effects of lead. CONCLUSION This study emphasizes that many focal sources of lead poisoning still remain especially in the unorganized sector. In cases presenting with unexplained neurotoxicity, specific occupational and environmental inquiry for chemical poisoning, with special consideration for lead, should be actively pursued.
Adolescent ; Air Pollution, Indoor ; adverse effects ; Case-Control Studies ; Child ; Child, Preschool ; Disease Outbreaks ; Female ; Humans ; India ; epidemiology ; Infant ; Inhalation Exposure ; adverse effects ; Jewelry ; poisoning ; Lead ; blood ; standards ; Lead Poisoning ; epidemiology ; pathology ; physiopathology ; Male ; Metallurgy ; Neurotoxicity Syndromes ; epidemiology ; pathology ; physiopathology ; Poverty Areas ; Risk Factors

OBJECTIVEIn order to minimize lead pollution and to protect the identified individuals with high blood lead level from lead contamination, an epidemiological study was carried on children living around the village and township-owned lead industries in Tianying town.

METHODSEnvironmental monitoring: lead levels in air, soil, drinking water and crops were measured. Biological monitoring: 959 children aged 5 - 12 years were selected from villages where the lead smelters located near the residential areas and the battery disassembling was done in some families. The control children (207 pupils) were from other villages without lead exposure. Blood lead, ZnPP and teeth lead were determined. Height, weight and head circle of children and IQ scores were measured.

RESULTSThe environment was seriously polluted. The average lead concentrations in air and soils were 8.5 times and 10 times of the MACs (national health standard) respectively. Eighty-five per cent the air samples with lead concentrations higher than the national health standard. Local crops and wheat at farmers' home were also contaminated by lead dust, with. Lead content being 24 times higher than the standard. The mean blood lead and ZnPP levels of children lived in the polluted areas were 496 microgram/L and 9.41 microgram/g Hb respectively. The lead exposure caused adverse effects on children's IQ and physical development.

CONCLUSIONIt is necessary to remove and reduce currently active sources of lead pollution in the community and to increase public awareness of potential health effects of lead exposure.

Air Pollutants ; analysis ; Child ; Child Development ; drug effects ; Child, Preschool ; China ; Crops, Agricultural ; chemistry ; Environmental Monitoring ; methods ; Environmental Pollution ; adverse effects ; analysis ; Female ; Health Status ; Humans ; Industrial Waste ; adverse effects ; analysis ; Lead ; adverse effects ; blood ; Male ; Soil Pollutants ; analysis ; Suburban Health ; standards ; Urban Health ; standards