scholarly journals Rapid diagnosis of MCAD deficiency: quantitative analysis of octanoylcarnitine and other acylcarnitines in newborn blood spots by tandem mass spectrometry

1997 ◽  
Vol 43 (11) ◽  
pp. 2106-2113 ◽  
Author(s):  
Donald H Chace ◽  
Steven L Hillman ◽  
Johan L K Van Hove ◽  
Edwin W Naylor
Keyword(s):  
Mass Spectrometry ◽  
Tandem Mass Spectrometry ◽  
Newborn Screening ◽  
Chain Length ◽  
Filter Paper ◽  
Tandem Mass ◽  
Mcad Deficiency ◽  
Medium Chain ◽  
Blood Spots ◽  
Medium Chain Length

Abstract We report the application of tandem mass spectrometry to prospective newborn screening for medium-chain acyl-CoA dehydrogenase (MCAD) deficiency. MCAD deficiency is diagnosed from dried blood spots on filter paper cards from newborns on the basis of the increase of medium chain length acylcarnitines identified by isotope dilution mass spectrometry methods. A robust and accurate semiautomated method for the analysis of medium chain length acylcarnitines as their butyl esters was developed and validated. Quantitative data from the analyses of 113 randomly collected filter paper blood spots from healthy newborns showed low concentrations of medium chain length acylcarnitines such as octanoylcarnitine. The maximum concentration of octanoylcarnitine was 0.22 μmol/L, with the majority being at or below the detection limit. In all 16 blood spots from newborns with confirmed MCAD deficiency, octanoylcarnitine was highly increased [median 8.4 μmol/L (range 3.1–28.3 μmol/L)], allowing easy detection. The concentration of octanoylcarnitine was significantly higher in these 16 newborns (<3 days of age) than in 16 older patients (ages 8 days to 7 years) with MCAD deficiency (median 1.57 μmol/L, range 0.33–4.4). The combined experience of prospective newborn screening in Pennsylvania and North Carolina has shown a disease frequency for MCAD deficiency of 1 in 17 706. No false-positive and no known false-negative results have been found. A validated method now exists for prospective newborn screening for MCAD deficiency.

Incorporating the measurement of EDTA in dried blood spots (DBS) by tandem mass spectrometry in routine newborn screening

2014 ◽  
Vol 47 (15) ◽  
pp. 144
Author(s):  
Lawrence J. Fisher ◽  
Osama Y. Al-Dirbashi ◽  
Svetlana Ogrel ◽  
Nathan McIntosh ◽  
Michael T. Geraghty ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Tandem Mass Spectrometry ◽  
Newborn Screening ◽  
Dried Blood Spots ◽  
Tandem Mass ◽  
Blood Spots

scholarly journals Validation of Accuracy-based Amino Acid Reference Materials in Dried-Blood Spots by Tandem Mass Spectrometry for Newborn Screening Assays

1999 ◽  
Vol 45 (8) ◽  
pp. 1269-1277 ◽  
Author(s):  
Donald H Chace ◽  
Barbara W Adam ◽  
S Jay Smith ◽  
J Richard Alexander ◽  
Steven L Hillman ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Amino Acids ◽  
Amino Acid ◽  
Tandem Mass Spectrometry ◽  
Newborn Screening ◽  
Dried Blood Spots ◽  
Tandem Mass ◽  
Blood Spots ◽  
Amino Acid Contents ◽  
Amino Acid Concentrations

Abstract Background: Advances in technology and the earlier release of newborns from hospitals have pressed the demand for accurate calibration and improved interlaboratory performance for newborn screening tests. As a first step toward standardization of newborn screening aminoacidopathy tests, we have produced six-pool sets of multianalyte dried-blood-spot amino acid reference materials (AARMs) containing predetermined quantities of five amino acids. We describe here the production of the AARMs, validation of their amino acid contents, and characterization of their homogeneity and their stability in storage. Methods: To each of six portions of a pool of washed erythrocytes suspended in serum we added Phe (0–200 mg/L), Leu (0–200 mg/L), Met (0–125 mg/L), Tyr (0–125 mg/L), and Val (0–125 mg/L). Six-pool sets (1300) were prepared, dried, and packaged. We used isotope-dilution mass spectrometry to estimate the endogenous amino acid concentrations of the AARMs and validate their final amino acid concentrations. We used additional tandem mass spectrometry analyses to examine the homogeneity of amino acid distribution in each AARM, and HPLC analyses to evaluate the stability of the amino acid contents of the AARMs. Results: The absolute mean biases across the analytic range for five amino acids were 2.8–9.4%. One-way ANOVAs of the homogeneity results predicted no statistically significant differences in amino acid concentrations within the blood spots or within the pools (P >0.05). Regression slopes (0 ± 0.01) for amino acid concentrations vs storage times and their P values (>0.05) showed no evidence of amino acid degradation at ambient temperatures, 4 °C, or −20 °C during the intervals tested. Conclusion: The validation, homogeneity, and stability of these blood spots support their use as a candidate national reference material for calibration of assays that measure amino acids in dried-blood spots.

scholarly journals Rapid 2nd-Tier Test for Measurement of 3-OH-Propionic and Methylmalonic Acids on Dried Blood Spots: Reducing the False-Positive Rate for Propionylcarnitine during Expanded Newborn Screening by Liquid Chromatography–Tandem Mass Spectrometry

2007 ◽  
Vol 53 (7) ◽  
pp. 1364-1369 ◽  
Author(s):  
Giancarlo la Marca ◽  
Sabrina Malvagia ◽  
Elisabetta Pasquini ◽  
Marzia Innocenti ◽  
Maria Alice Donati ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Liquid Chromatography ◽  
Tandem Mass Spectrometry ◽  
Newborn Screening ◽  
False Positive ◽  
Tandem Mass ◽  
Blood Spots ◽  
Chromatography Tandem Mass Spectrometry ◽  
Liquid Chromatography Tandem Mass ◽  
Positive Results

Abstract Background: The expansion of newborn screening programs has increased the number of newborns diagnosed with inborn errors of metabolism in the presymptomatic phase, but it has also increased the number of costly, stress-producing false-positive results. Because propionylcarnitine (C3) is one of the analytes most frequently responsible for false-positive results, we aimed to develop a rapid liquid chromatography–tandem mass spectrometry (LC-MS/MS) method to identify free methylmalonic (MMA) and 3-OH propionic (3OH-PA) acids in blood spots. Methods: We studied newborn screening spots from 250 healthy controls; 124 from infants with abnormal C3, of whom only 5 (4%) were truly affected; 124 from infants with altered isolated methylmalonylcarnitine; and 4 from clinically diagnosed patients. Whole blood was eluted from a 3.2-mm dried blood spot by a CH3CN/H2O 7:3 and 5 mL/L formic. This extract was injected into a LC-MS/MS equipped with pneumatically assisted electrospray without derivatization. Total analysis time was 5 min per sample. Results: The assays were linear up to 3300 nmol/L for both metabolites. Intra- and interassay imprecision data were 3.6%–8% and 3.1%–6%, respectively, for MMA and 5.2%–20% and 3.6%–17% for 3OH-PA. Limit of detection and limit of quantitation were 1.95 and 4.2 μmol/L, respectively, for MMA and 8 and 10 μmol/L for 3OH-PA. The recoveries were 92.9%–106.1%. No deterioration was noted on the columns after 500 chromatographic runs. If the new method had been used as a 2nd-tier test for the 124 samples, only the 5 true positives would have been recalled for additional samples, and the positive predictive value would have been 100%. Conclusions: This method has the potential to markedly reduce false-positive results and the associated costs and anxiety. It may also be suitable for diagnosing and routinely monitoring blood spots for methylmalonic aciduria and propionic acidemia.

Newborn Screening by Tandem Mass Spectrometry for Medium-Chain Acyl-CoA Dehydrogenase Deficiency: A Cost-Effectiveness Analysis

PEDIATRICS ◽  
2003 ◽  
Vol 112 (5) ◽  
pp. 1005-1015 ◽  
Author(s):  
L. N. Venditti ◽  
C. P. Venditti ◽  
G. T. Berry ◽  
P. B. Kaplan ◽  
E. M. Kaye ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Cost Effectiveness ◽  
Tandem Mass Spectrometry ◽  
Newborn Screening ◽  
Dehydrogenase Deficiency ◽  
Cost Effectiveness Analysis ◽  
Tandem Mass ◽  
Medium Chain ◽  
Effectiveness Analysis ◽  
Chain Acyl

scholarly journals Tandem Mass Spectrometry for the Direct Assay of Enzymes in Dried Blood Spots: Application to Newborn Screening for Krabbe Disease

2004 ◽  
Vol 50 (3) ◽  
pp. 638-640 ◽  
Author(s):  
Yijun Li ◽  
Knut Brockmann ◽  
Frantisek Turecek ◽  
C Ronald Scott ◽  
Michael H Gelb
Keyword(s):  
Mass Spectrometry ◽  
Tandem Mass Spectrometry ◽  
Newborn Screening ◽  
Dried Blood Spots ◽  
Krabbe Disease ◽  
Tandem Mass ◽  
Blood Spots ◽  
Direct Assay

scholarly journals Tandem Mass Spectrometry for the Direct Assay of Lysosomal Enzymes in Dried Blood Spots: Application to Screening Newborns for Mucopolysaccharidosis I

2008 ◽  
Vol 54 (12) ◽  
pp. 2067-2070 ◽  
Author(s):  
Sophie Blanchard ◽  
Martin Sadilek ◽  
C Ronald Scott ◽  
Frantisek Turecek ◽  
Michael H Gelb
Keyword(s):  
Mass Spectrometry ◽  
Tandem Mass Spectrometry ◽  
Newborn Screening ◽  
Lysosomal Enzymes ◽  
Internal Standard ◽  
Dried Blood Spots ◽  
Simple Liquid ◽  
Tandem Mass ◽  
Mucopolysaccharidosis I ◽  
Blood Spots

Abstract Background: Treatments now available for mucopolysaccharidosis I require early detection for optimum therapy. Therefore, we have developed an assay appropriate for newborn screening of the activity of the relevant enzyme, α-L-iduronidase. Methods: We synthesized a new α-L-iduronidase substrate that can be used to assay the enzyme by use of tandem mass spectrometry together with an internal standard or by fluorometry. The assay uses a dried blood spot on a newborn screening card as the enzyme source. The assay protocol uses a simple liquid-liquid extraction step before mass spectrometry. We optimized enzyme reaction conditions and procedures for the assay, including the concentration of substrate, the reaction pH, the incubation time, and mass spectrometer operation. We also assessed inter- and intraassay imprecision. Results: When the assay was tested on dried blood spots, the α-L-iduronidase activity measured for 5 patients with mucopolysaccharidosis I was well below the interval found for 10 randomly chosen newborns. Inter- and intraassay imprecision were <10%. The synthesis of the α-L-iduronidase substrate is practical for use on a scale needed to support newborn screening demands. Conclusions: This newly developed tandem mass spectrometry assay has the potential to be adopted for newborn screening of mucopolysaccharidosis I. This assay has advantages over a previously reported assay also developed in this laboratory and has the potential to be performed in a multiplex fashion to measure several lysosomal enzymes relevant to treatable lysosomal storage diseases.

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