Last data update: May 13, 2024. (Total: 46773 publications since 2009)
Records 1-8 (of 8 Records) |
Query Trace: Adam BW[original query] |
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Galactose-1-phosphate uridyltransferase dried blood spot quality control materials for newborn screening tests
Adam BW , Flores SR , Hou Y , Allen TW , De Jesus VR . Clin Biochem 2014 48 (6) 437-42 OBJECTIVES: We aimed to prepare dried-blood-spot (DBS) quality control (QC) materials for galactose-1-phosphate uridyltransferase (GALT), to evaluate their stability during storage and use, and to evaluate their performance in five DBS GALT test methods. DESIGN AND METHODS: We prepared and characterized GALT-normal and GALT-deficient DBS materials and compared GALT activities in DBSs after predetermined storage intervals at controlled temperatures and humidities. External evaluators documented the suitability of the DBS QC materials for use in five GALT test methods. RESULTS: GALT activity losses from DBSs stored in low (<30%) humidity for 14days at 45 degrees C, 35days at 37 degrees C, 91days at room temperature, 182days at 4 degrees C, and 367days at -20 degrees C were 54%, 53%, 52% 23%, and 7% respectively. In paired DBSs stored in high humidity (>50%) for identical intervals, losses were: 45 degrees C-68%; 37 degrees C-79%; room temperature-72%, and 4 degrees C-63%. GALT activities in DBSs stored at 4 degrees C were stable throughout 19 excursions to room temperature. Twenty-five of 26 external evaluators, using five different GALT test methods, classified the GALT-deficient DBSs as "outside normal limits". All evaluators classified the GALT-normal DBSs as "within normal limits". CONCLUSIONS: Most of the GALT activity loss from DBSs stored at elevated or room temperature was attributable to the effects of storage temperature. Most of the loss from DBSs stored at 4 degrees C was attributable to the effects of elevated humidity. Loss from DBSs stored at -20 degrees C was insignificant. The DBS materials were suitable for monitoring performance of all five GALT test methods. |
Succinylacetone as primary marker to detect tyrosinemia type I in newborns and its measurement by newborn screening programs.
De Jesus VR , Adam BW , Mandel D , Cuthbert CD , Matern D . Mol Genet Metab 2014 113 67-75 Tyrosinemia type I (TYR I) is caused by autosomal recessive fumarylacetoacetate hydrolase deficiency and is characterized by development of severe liver disease in infancy and neurologic crises. If left untreated, most patients die of liver failure in the first years of life. Intervention with medication is effective when initiated during the first month of life. This improvement in the treatment of TYR I patients influenced the decision to include TYR I in the US Secretary of the Department of Health and Human Services' (HHS) Recommended Uniform Screening Panel. However, while tyrosine is routinely measured in newborn screening (NBS) by tandem mass spectrometry (MS/MS), elevated tyrosine levels are not specific to TYR I. To improve the specificity of NBS for TYR I, several assays were developed to measure succinylacetone (SUAC) in dried blood spots (DBS). SUAC is a pathognomonic marker of TYR I, and its detection by NBS MS/MS is possible. This review of the current status of NBS for TYR I in the US is the result of discussions at the HHS Secretary's (Discretionary) Advisory Committee on Heritable Disorders in Newborns and Children about the inconsistent implementation of effective NBS for TYR I in the US. We sought to understand the different TYR I screening practices in US NBS programs. Results indicate that 50 out of 51 NBS programs in the US screen for TYR I, and a successful SUAC performance evaluation scheme is available from the Centers for Disease Control and Prevention. Programmatic and methodological barriers were identified that prevent widespread adoption of SUAC measurements in NBS laboratories. However, since SUAC detection is currently the best approach to NBS for TYR I, a further delay of the addition of SUAC measurement into NBS procedures is discouraged. SUAC measurement should improve both the false positive and false negative rate in NBS for TYR I thereby yielding the desired benefits for affected patients at no expense to the overall population served. |
Stabilities of intact hemoglobin molecules and hemoglobin peptides in dried blood samples
Adam BW , Haynes CA , Chafin DL , De Jesus VR . Clin Chim Acta 2013 429 59-60 Sickle cell diseases are inborn blood disorders caused by the presence of an abnormal form of hemoglobin, hemoglobin S (HbS). Mortality from sickle cell disease during the first 3 to 4 years of life can be virtually eliminated by newborn screening and appropriate follow-up and treatment [1]. Three sickle cell diseases (sickle cell anemia, sickle hemoglobin C disease and sickle β thalassemia) are included in the United States' recommended uniform newborn screening panel [2]. HbS is the newborn screening marker for all three disorders. | The Newborn Screening Quality Assurance Program of the Centers for Disease Control and Prevention (CDC) prepares and validates dried-blood spot (DBS) proficiency testing materials to assist laboratories with monitoring the performance of their newborn screening tests [3]. As part of routine evaluations of marker stabilities in DBS samples, we used measurements by high performance liquid chromatography (HPLC) and liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) methods to compare the stabilities of HbA and HbS in DBSs stored for predetermined intervals at elevated temperature (37°C) and low (<30%) or high (>50%) humidity. The objectives of these studies were to measure separately the contributions of heat and humidity to the degradation of HbS and HbA in DBS samples and to evaluate the level of concordance between results from the two analysis methods used. |
Stabilities of hemoglobins A and S in dried blood spots stored under controlled conditions
Adam BW , Chafin DL , De Jesus VR . Clin Biochem 2013 46 (12) 1089-1092 OBJECTIVE: We aimed to measure separately the contributions of heat and humidity to changes in levels of hemoglobins A and S in dried-blood-spot (DBS) samples. DESIGN AND METHODS: We stored paired sets of DBSs at 37 degrees C for predetermined intervals in low-humidity and high-humidity environments. Hemoglobin A and S levels of all samples in each complete set were measured in a single high performance liquid chromatography run. RESULTS: During the one-month storage intervals, both hemoglobin species lost about 35% of initial levels in low-humidity storage and almost all of initial levels in high-humidity storage. CONCLUSIONS: Minimizing both humidity and temperature in the transportation and storage environments of DBS samples is essential to maintaining the integrity of the hemoglobin tetramer molecules. |
Performance of succinylacetone assays and their associated proficiency testing outcomes
Adam BW , Hall EM , Meredith NK , Lim TH , Haynes CA , De Jesus VR , Hannon WH . Clin Biochem 2012 45 (18) 1658-63 BACKGROUND: Succinylacetone (SUAC) is the primary metabolic marker for hepatorenal tyrosinemia. MATERIALS AND METHODS: We used results reported for dried-blood-spot proficiency testing (PT) specimens and hepatorenal tyrosinemia patients' newborn screening (NBS) samples to demonstrate analytic biases in SUAC recoveries and differences in presumptive clinical classifications. RESULTS: SUAC recoveries from non-kit and NeoBase kit tandem mass spectrometry methods were markedly different. Kit users that set high cutoff values submitted discordant clinical assessments of "within normal limits" for PT specimens enriched with 10-15mcmol SUAC/L in blood. SUAC levels in tyrosinemia patients' NBS samples analyzed by NeoBase kit were lower than those in samples analyzed by non-kit methods. CONCLUSIONS: From 2009 to 2011, analytic biases in SUAC recoveries were consistent. Discordant clinical assessments of PT specimens were associated with high cutoff values for NeoBase kit results. Method-related differences in SUAC concentrations of tyrosinemia patients' samples were consistent with those of PT specimens. |
The stability of markers in dried-blood spots for recommended newborn screening disorders in the United States
Adam BW , Hall EM , Sternberg M , Lim TH , Flores SR , O'Brien S , Simms D , Li LX , De Jesus VR , Hannon WH . Clin Biochem 2011 44 1445-50 OBJECTIVE: We aimed to measure separately the contributions of heat and humidity to changes in levels of 34 markers of inborn disorders in dried-blood-spot (DBS) samples. DESIGN AND METHODS: We stored paired sets of DBSs at 37 degrees C for predetermined intervals in low-humidity and high-humidity environments. Marker levels of all samples in each complete sample set were measured in a single analytic run. RESULTS: During the 30+/-5day studies, galactose-1-phosphate uridyltransferase and biotinidase lost almost 65% of initial activities in low-humidity storage; most of the degradation in 27 other markers was attributable to adverse effects of high-humidity storage; seven markers in DBSs stored at high humidity lost more than 90% of initial levels by the end of the study and 4 of the 7 lost more than 50% of initial levels within the first week of storage. CONCLUSIONS: Minimizing both humidity and temperature in DBS transportation and storage environments is essential to maintaining sample integrity. |
The preparation and storage of dried-blood spot quality control materials for lysosomal storage disease screening tests
Adam BW , Orsini JJ Jr , Martin M , Hall EM , Zobel SD , Caggana M , Hannon WH . Clin Biochem 2011 44 704-10 OBJECTIVE: We aimed to prepare dried-blood spot (DBS) quality control (QC) materials for lysosomal storage disease (LSD) screening tests and to determine optimum blood and DBS storage conditions. METHODS: We compared enzyme activities of five LSD markers in adult blood, umbilical-cord blood, and leukocyte-reduced blood. We measured activities in liquid blood and DBSs after predetermined intervals at controlled temperatures and humidities. RESULTS: Lysosomal-enzyme activity levels in umbilical-cord blood mimicked those in newborn screening samples. Lysosomal-enzyme activities in leukocyte-reduced blood were lower than in LSD-positive patient samples. Enzyme activities were stable in refrigerated liquid blood for 32days and in frozen DBSs stored at low humidity for a year. Activity losses from DBSs after 34days at 37+/-1 degrees C were 35-66% in low humidity and 61-100% in high humidity. CONCLUSIONS: Umbilical-cord blood is the preferred matrix for LSD-normal DBS QC materials. Leukocyte-reduced blood is lysosomal enzyme-deficient. Failure to control humidity during DBS storage results in loss of lysosomal-enzyme activities. |
Preliminary proficiency testing results for succinylacetone in dried blood spots for newborn screening for tyrosinemia type I
Adam BW , Lim TH , Hall EM , Hannon WH . Clin Chem 2009 55 (12) 2207-13 BACKGROUND: Succinylacetone (SUAC) is the primary metabolite accumulated in tyrosinemia type I-an inborn error of metabolism that, if untreated, can cause death from liver failure during the first months of life. Newborn screening laboratories measure SUAC in dried blood spot (DBS) samples to detect asymptomatic tyrosinemia type I. We used panels of SUAC-enriched DBSs to compare and evaluate the performance of these screening tests. METHODS: We prepared sets of DBS materials enriched with predetermined SUAC concentrations and distributed samples of these materials, along with a screening practices questionnaire, to laboratories that perform SUAC tests. We compared their reported SUAC concentrations and questionnaire responses to identify screening practices that affect SUAC test outcomes. RESULTS: Data from 2 pilot surveys showed large differences among laboratories in SUAC recoveries, reproducible within-laboratory recoveries, and stable performance of the DBS materials. Results from 257 proficiency test analyses contained a total of 6 false-negative misclassifications. Reported recoveries of added SUAC ranged from 0 to >200%. Low-biased SUAC recoveries were associated with 1 method used by 5 laboratories. All laboratories that reported SUAC recoveries ≥100% used DBS matrix calibrators. CONCLUSIONS: The wide ranges of SUAC concentrations reported for pilot and proficiency testing specimens demonstrate a need to harmonize quantitative results among laboratories. Although DBS matrix calibrators are important for optimizing SUAC recoveries, the preparation of these calibrators is not standardized among laboratories. Certified DBS-based SUAC calibrators are needed for accuracy and harmonization. |
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