PubMed Health⌕ Search

Biomedical subjects

H Y Yee

Publications and source records attributed to H Y Yee.

16 recordsLinked to original sources
PubMed1998

A community outreach lead screening program using capillary blood collected on filter paper.

OBJECTIVE: To test whether a method of fingerstick blood sample collection onto filter paper could be used as an alternative screening method in the field in settings where environmental lead contamination is a high risk. METHOD: Members of the Pediatric Mobile Team of Children's Hospital of Michigan, Detroit, collected paired venous and capillary blood samples from 120 children, aged 6 months to 6 years, who presented for services at any of 7 sites located in decaying neighborhoods of older sections of Detroit. All samples were analyzed for lead content by graphite furnace atomic absorption spectrometry. RESULTS: When filter paper samples with blood lead levels of 0.48 micromol/L (10 microg/dL) or higher were compared with matched venous samples, the concordance coefficient was 0.96. The sensitivity and specificity of the filter paper samples relative to the venous samples for a cutoff of 0.48 micromol/L (10 microg/dL) or higher were 94% and 99%, respectively, with a positive predictive value of 97%. However, at a cutoff of 0.72 micromol/L (15 microg/dL), the sensitivity and specificity dropped to 75% and 98%, respectively, with filter paper samples underreporting blood lead values. At any cutoff point (0.48, 0.72, or 0.96 micromol/L [10, 15, or 20 microg/dL]), the filter paper method was highly specific for lead. CONCLUSIONS: Capillary filter paper sampling is an accurate and practical alternative to venous sampling for blood lead screening using 0.48 micromol/L (10 microg/dL) as the cutoff. The filter paper method predicts levels of 0.72 micromol/L (15 microg/dL) or higher less well. The cause of divergent values above 0.72 micromol/L (15 microg/dL) is not clear. Environmental contamination of capillary filter paper, however, does not seem to be an explanation.

Capillaries↗
PubMed1996

A new filter paper method to measure capillary blood lead level in children.

OBJECTIVE: To develop and evaluate a new filter paper method to determine capillary blood lead levels accurately in children. DESIGN: Paired comparison of lead levels determined in capillary whole blood dried on filter paper with lead levels in venous whole blood samples determined by a reference method. SETTING: Children's Hospital of Michigan clinics, Detroit. PATIENTS: One hundred children aged 9 months to 6 years. INTERVENTIONS: Lead concentrations determined in capillary whole blood samples dried on filter paper were compared with concentrations measured in paired venous whole blood samples by a reference method. MAIN OUTCOME MEASURES: Comparability of the two lead assay methods was assessed with the concordance coefficient. The sensitivity, specificity, and positive predictivity of the capillary filter paper method relative to the reference method were determined at three intervention decision concentrations of blood lead defined by the Centers for Disease Control and Prevention. RESULTS: There was high agreement between the two assay methods, with a concordance coefficient of O.96. The capillary filter paper assay had a sensitivity of 90% and specificity of 90% for differentiating blood lead levels of 0.48 mumol/L (10 micrograms/dL) or more. Blood lead levels of 0.72 mumol/L (15 micrograms/dL) or more and 0.96 mumol/L (20 micrograms/dL) or more were identified with 98% and 94% sensitivity and 98% and 99% specificity, respectively. Positive predictivity was 93%, 98%, and 97%, respectively, at the three blood lead concentration decision points. CONCLUSION: The capillary filter paper method for blood lead analysis described herein provides a convenient, sensitive, accurate, and inexpensive method to examine children for elevated blood lead levels.

Child↗
PubMed1982

Quantitative determination of lecithin and sphingomyelin in amniotic fluid.

A quantitative method for lecithin and sphingomyelin is presented. In this method, which may be calibrated with a primary standard phosphate salt or pure phospholipids, 2 mL of amniotic fluid is extracted, and the solvent passed through a column of hydroxyapatite to remove all phospholipids except lecithin and sphingomyelin. After evaporation, the residue is treated with methanolic sodium hydroxide, which hydrolyzes lecithin to inorganic phosphate and a methyl ester. The unreacted sphingomyelin is removed by extraction, and the solvent evaporated. Both fractions are digested and assayed for phosphate by reduced phosphomolybdate. The total time required is 2 h. Analytical recoveries were 91-97%, and excellent agreement was found for controls. Amniotic fluid specimens were assayed to illustrate application of the proposed method. If this method is used for obtaining a lecithin/sphingomyelin ratio, a new ranges must be established, as this method is not equivalent to thin-layer chromatographic ones.

Amniocentesis↗
PubMedDate not supplied

Measurement of benzoylecgonine in whole blood using the Abbott ADx analyzer.

An alternate procedure has been developed for the processing of whole blood for the estimation of benzoylecgonine with the use of the Abbott ADx reagents and analyzer. This procedure allows for handling of relatively large numbers of samples without the need to evaporate extraction solvent. Blood samples were diluted with an equal volume of phosphate buffer-methanol (80:20 v/v), and the proteins were removed by centrifugation through a membrane filter device. A comparison of the proposed method with an acetone solvent extraction procedure has been made, and results were shown to be equivalent. Recoveries of 94-105% benzoylecgonine were obtained for added concentrations of 25-500 ng/mL.

Cocaine↗
PubMedDate not supplied

Measurement of lead in blood by graphite furnace atomic absorption spectrometry.

A simple method of deproteinizing whole blood with an 0.8M (5%, v/v) nitric acid solution containing Triton X-100 (0.1%, v/v) is described. The resulting supernatant is used for the measurement of lead by Zeeman graphite furnace atomic absorption spectrometry using calibration with aqueous standards. Recoveries ranged from 97.7-105.6% when an aqueous lead solution was added to a deproteinized sample supernatant and from 98.5-104.5% when whole blood control material was added to a whole blood sample. At a blood lead concentration of 11.2 micrograms/dL, the within- and between-run coefficients of variation were both approximately 5%. Comparison of the proposed method versus one using a recommended matrix modifier gave a regression equation of Y(proposed) = 0.99x(matrix modifier)-0.36, with a correlation coefficient of r = 0.994 (n = 54).

Graphite↗
PubMedDate not supplied

An improved capillary blood-filter paper-graphite furnace atomic absorption spectrometric method for lead screening.

A revised procedure for processing a capillary blood sample collected on filter paper (FP) for analysis by graphite furnace atomic absorption spectrometry (GFAAS) is described. A 1/4-in. diameter disk of the dried FP sample was used, and a correlation of 0.975 with a false-positive rate of 0.8% and a false-negative rate of 1.7% was found when the results from the FP sample and its corresponding venous sample were compared. Several analytical variables were investigated, and the following was found: blood samples with hematocrit values of 30-39% did not show any significant differences between the paired FP and venous lead results; filter paper blank values were < 2 micrograms/dl with the use of aqueous standards without correction and 0.1 microgram/dl with paper blank correction; and during the collection of 163 samples from 6 different urban sites over a period of 1 year, no environmental lead contamination was encountered based upon the good agreement between all of the paired FP and venous lead results. The method described is easier to perform than an earlier version. All indications suggest that a fingerstick capillary blood sample collected on filter paper is suitable for lead screening. Proper precautions must always be taken to guard against contamination.

Blood Specimen Collection↗