串联质谱技术筛查新生儿甲基丙二酸血症回顾性分析

目的回顾性分析串联质谱技术在新生儿甲基丙二酸血症筛查中的应用。方法利用液相串联质谱技术筛查2015年10月至2017年12月在该院进行48项遗传代谢病检测的样本近10万例,对初筛为阳性的样本做召回复查,对复查仍为阳性的样本通过气相色谱质谱技术进行尿有机酸分析,并采用基因测序作进一步确诊。结果通过对近10万例样本进行筛查,发现132例疑似甲基丙二酸血症、丙酸血症样本,确诊甲基丙二酸血症1例,丙酸血症1例。结论串联质谱技术对甲基丙二酸血症的诊断有重要的提示作用,需密切结合气相色谱质谱和测序技术鉴别诊断丙酸血症。     

LC-MS/MS技术检测新生儿干血斑甲基丙二酸、同型半胱氨酸cut-off值的建立

目的探讨建立高效液相色谱质谱-串联质谱联合检测(liquid chromatography-tandem mass spectrometry,LC-MS/MS)技术检测新生儿干血斑甲基丙二酸(methylmalonic acid,MMA)和同型半胱氨酸(homocysteine,Hcy)cut-off值的方法。方法收集本院分娩的新生儿MS/MS筛查中C3、C3/C2和C3/C0任一指标偏高的正常干血斑样本作为阴性样本,同时收集通过尿气相色谱质谱结合循环酶法确诊为甲基丙二酸血症合并同型半胱氨酸血症患儿的初筛干血斑样本作为阳性样本,采用LC-MS/MS技术分别检测该两类样本中MMA和Hcy的浓度。应用百分位数法并结合ROC曲线分析确定使用LC-MS/MS技术检测MMA和Hcy的cut-off值。结果共收集1 015例阴性样本和16例MMA患儿阳性样本,LC-MS/MS技术检测阳性样本的MMA和Hcy浓度均明显高于阴性样本,差异具有统计学意义(U_(MMA)=8.5,U_(Hcy)=23.5,P均0.05);MMA和Hcy的ROC曲线下面积(AUC~(ROC))均为0.999,cut-off值分别为3.145μmol/L和7.295μmol/L,诊断特异性分别为99.5%和99.3%。结论百分位数法结合ROC曲线法可用于确定本地区MMA患儿干血斑中MMA和Hcy的cut-off值,且本地区人群的MMA和Hcy cut-off值明显低于梅奥诊所提供的cut-off值。     

串联质谱技术检测羊水中代谢物在甲基丙二酸血症产前诊断中的价值

目的探讨串联质谱技术检测羊水中丙酰基肉碱(C3)在甲基丙二酸血症(MMA)产前诊断中的价值。方法收集孕16～28周孕妇羊水样品并制成羊水滤纸片,进一步用非衍生化串联质谱方法定量检测样品中C3、乙酰基肉碱(C2)和游离肉碱(C0)水平,对疑似阳性的胎儿进行MMA基因诊断。结果共有730例孕妇自愿要求完善羊膜腔穿刺检测。其中有710例为对照组,初步制定本室相应指标的参考区间(C3:0.07～0.64μmol/L;C3/C0:0.01～0.07;C3/C2:0.08～0.45);另外20例为病例组,其中2例羊水中C3、C3/C0、C3/C2检测值明显高于参考区间,通过基因检测明确诊断该胎儿为MMA。质谱检测结果与基因检测结果符合率为100%。结论 MS/MS技术检测羊水中C3、C3/C0、C3/C2的水平可用于MMA的产前诊断,其中C3和C3/C0的区分度最好,C3/C2区分度最差。     

串联质谱技术检测羊水中丙酰基肉碱在甲基丙二酸血症产前诊断中的价值

目的探讨串联质谱技术检测羊水中丙酰基肉碱(C3)在甲基丙二酸血症(MMA)产前诊断中的价值。方法收集孕16～28周孕妇羊水样品并制成羊水滤纸片,进一步用非衍生化串联质谱方法定量检测样品中C3、乙酰基肉碱(C2)和游离肉碱(C0)水平,对疑似阳性的胎儿进行MMA基因诊断。结果共有730例孕妇自愿要求完善羊膜腔穿刺检测。其中有710例为对照组,初步制定本室相应指标的参考区间(C3:0.07～0.64μmol/L;C3/C0:0.01～0.07;C3/C2:0.08～0.45);另外20例为病例组,其中2例羊水中C3、C3/C0、C3/C2检测值明显高于参考区间,通过基因检测明确诊断该胎儿为MMA。质谱检测结果与基因检测结果符合率为100%。结论 MS/MS技术检测羊水中C3、C3/C0、C3/C2的水平可用于MMA的产前诊断,其中C3和C3/C0的区分度最好,C3/C2区分度最差。     

2018-2019年上饶市串联质谱筛查新生儿遗传代谢病情况分析

目的 探讨串联质谱检测在新生儿疾病筛查中的临床应用价值,明确串联质谱筛查在上饶市的初筛阳性率及确诊阳性率,统计出新生儿遗传代谢病在上饶市的总体发病率.方法 回顾性分析2018年10月至2019年8月在上饶市妇幼保健院新生儿筛查中心进行遗传代谢病筛查的15207例新生儿筛查结果;利用串联质谱技术对新生儿血液样本进行氨基酸、有机酸、脂肪酸、游离肉碱和酯酰肉碱谱检测,根据记录不同质荷比的离子质量谱,通过待测样品峰面积与内标峰面积之比获得定量结果,通过线性回归计算出所测样品各项指标的浓度.根据结果分析初筛阳性情况,明确串联质谱筛查在上饶市的初筛阳性率及确诊阳性率,对初筛阳性患儿召回复查后仍为阳性的患儿进行实验室检测分析,观察记录不同遗传代谢病的临床症状,以便早期发现遗传代谢病患儿并及时予以有效治疗,保障儿童正常体格发育及智力发育.结果 诊断出短链酰基辅酶A脱氢酶缺乏症1例,中链酰基辅酶A脱氢酶缺乏症1例,瓜氨酸血症Ⅱ型1例,原发性肉碱缺乏症1例.结论 串联质谱技术应用于新生儿遗传代谢病筛查有利于疾病的早期发现和诊断,兼有超敏性、高特异性、高通量、可重复性的特点,有利于疾病的及早干预.     

珠海地区20364例新生儿遗传代谢病筛查结果分析

目的 初步了解并探讨珠海地区新生儿遗传代谢病筛查情况及发病率,为地区性防治出生缺陷提供有效依据。方法 选取2021年1月至2022年12月在珠海地区出生的20 364例新生儿作为研究对象,进行多种遗传代谢病筛查,对初筛阳性者召回复查,复查仍阳性者进行尿质谱分析和基因检测等明确诊断,统计分析初筛阳性率、总发病率等。结果 20 364例接受串联质谱筛查的新生儿中,初筛阳性人数687例,初筛阳性率为3.37%;初筛阳性召回人数621例,初筛阳性召回率为90.39%。经召回复查发现70例可疑阳性,筛查阳性率为0.34%,召回阳性率为11.27%,最终确诊7例,总发病率为1/2 909。其中,氨基酸代谢病2例(希特林蛋白缺乏症和高甲硫氨酸血症各1例)、脂肪酸代谢障碍4例(原发性肉碱缺乏症2例、中链酰基辅酶A脱氢酶缺乏症和极长链酰基辅酶A脱氢酶缺乏症各1例)、有机酸代谢病(甲基丙二酸血症)1例。7例确诊患儿中有6例进行了基因突变检测,并对其主要标志物及相关指标进行分析,其中氨基酸基因确诊2例,脂肪酸基因确诊3例,有机酸基因确诊1例。结论 珠海地区新生儿遗传代谢病总发病率为1/2 909,略低于该地...     

串联质谱用于顺德区新生儿代谢遗传病筛查工作的临床价值

目的探讨串联质谱用于顺德区新生儿代谢遗传病筛查工作的临床价值。方法以2014年2月至2015年3月顺德地区各镇街道医院收治的4 100例新生儿为对象,所有新生儿采用串联质谱法及荧光分析法进行代谢遗传病筛查,主要检查项目包含氨基酸代谢异常、有机酸代谢异常及脂肪酸代谢异常,并对确诊患儿进行流行病学特点、预后及随访分析。结果 4 100例新生儿,荧光分析组召回率较串联质谱组显著高,且荧光分析组新生儿代谢遗传病确诊率较串联质谱组显著低;串联质谱筛查结果显示氨基酸代谢病25例(59.52%),其中苯丙酮尿症13例,酪氨酸血症Ⅰ型2例,瓜氨酸血症Ⅰ型2例,枫糖尿症2例,精氨酸血症6例;有机酸代谢病14例(33.33%),甲基丙二酸血症9例,丙酸血症3例,生物素酶缺乏症2例;脂肪酸代谢异常3例(7.15%),肉碱棕榈酰转移酶Ⅱ缺乏症2例,原发性肉碱吸收障碍1例。结论串联质谱是一种高效、准确的新生儿代谢遗传病筛查技术,顺德地区新生儿代谢遗传病及时诊断对于一些可给予特殊饮食及药物干预的疾病具有较高的应用价值,同时可提高患儿预后,对提高新生儿生存质量意义重大。     

石家庄地区128 399例新生儿多种遗传代谢病串联质谱筛查结果分析

目的回顾性分析石家庄市新生儿多种遗传代谢病筛查情况,了解遗传代谢病单病种患病率及基因突变情况。方法采用串联质谱技术—非衍生法检测滤纸干血斑中11种氨基酸、30种酰基肉碱和游离肉碱的含量及相互之间的比值,对石家庄市2014年1月至2018年5月出生的新生儿进行多种遗传代谢病筛查,采用二代测序技术对疑似患儿进行基因突变检测,并用Sanger测序法验证。结果 128 399例新生儿中初筛阳性3 811例,阳性率为2.97%;召回3 620例,确诊102例,总体患病率为1/1 259,阳性预测值为2.8%(102/3 620)。102例患儿中氨基酸代谢异常患儿50例,其中苯丙酮尿症患儿35例(70%);有机酸代谢异常患儿36例,其中甲基丙二酸血症患儿34例(94.4%);脂肪酸代谢异常患儿16例,其中原发性肉碱缺乏症患儿9例(56.3%)。53例患儿基因测序及父母验证结果发现纯合突变4例、复合杂合突变37例、杂合突变11例,二代测序技术进行基因缺失重复检测时发现基因整体杂合缺失1例。基因测序共发现56种突变,其中11种未见报道。结论石家庄市新生儿遗传代谢病患病率较高的为苯丙酮尿症、甲基丙二酸血症和原发性肉碱缺乏症;初步构建了石家庄市遗传代谢病患儿基因突变谱,并发现多个未报道基因突变。     

扬州地区应用串联质谱技术进行新生儿遗传代谢病筛查的临床价值

目的 探讨串联质谱技术在扬州地区新生儿遗传代谢病筛查中的临床意义。方法 采用串联质谱技术对扬州地区2017年7月—2019年12月的新生儿进行遗传代谢病筛查,并对筛查结果为可疑阳性的新生儿进行基因检测。结果 共纳入新生儿25 771例。其中,初筛阳性435例,召回394例,确诊17例。在17例确诊患儿中,氨基酸代谢病10例、有机酸代谢病3例及脂肪酸氧化代谢病4例,死亡3例。结论 串联质谱技术在新生儿氨基酸代谢病、有机酸代谢病及脂肪酸氧化代谢病筛查中的广泛应用,对新生儿遗传代谢病的早期筛查、诊断及治疗具有重要意义。     

新生儿遗传代谢病串联质谱筛查技术应用研究

目的 分析新生儿遗传代谢病串联质谱筛查技术的应用价值。方法 选取 2021 年 3 月 24 日至 2021 年 11 月 24 日期间在我 院分娩的新生儿样本 4397 例为观察主体,分别进行常规法筛查（对照组）和串联质谱筛查（研究组）。对两组筛查结果为疑似 阳性的新生儿通过基因检测来进行确诊。结果 研究组疑似阳性的新生儿样本 438 例,初筛阳性率为 9.96%,召回 433 例,召回 确诊 5 例,灵敏度为 100.00％,阳性预测值 1.14％。而对照组似阳性的新生儿样本 719 例,初筛阳性率为 16.35%,召回 719 例, 召回确诊 2 例,灵敏度为 40.00％,阳性预测值 0.28％。两组的灵敏度比较,差异有统计学意义（P<0.05）。串联质谱筛查确诊 的新生儿中,有 3 例氨基酸代谢异常,占 60.00%;有 1 例有机酸代谢异常,占 20.00%;有 1 例脂肪酸代谢异常,占 20.00%。 所有确诊样本经过及时的治疗干预,诊治率达到 100.00％。结论 串联质谱筛查技术与常规筛查法相比,其临床应用价值更高, 能及时发现新生儿异常情况,为临床诊疗提供有效的信息,进而提高新生儿人口的生存质量。     

Role of liquid chromatography–high-resolution mass spectrometry (LC-HR/MS) in clinical toxicology

Background. Gas chromatography (GC) and liquid chromatography (LC) coupled with mass spectrometry (MS) are widely used to confirm drug screening results and for urine screening in presumed intoxicated patients. These techniques are better suited to targeted analysis than to general unknown screening and, due to the complexity of testing, results are seldom available rapidly enough to contribute to the immediate care of the patient. High resolution (HR)/MS with time-of-flight (TOF) or orbitrap instruments offer potential advantages in clinical toxicology. Comparison of GC-MS, LC-MS/MS and LC-HR/MS. For unknown analyses, GC-MS and LC-MS/MS require comparison of full-scan spectra against preestablished libraries. Operation in full-scan mode greatly reduces sensitivity and some drugs present in low but significant concentrations may be missed. Selected ion monitoring (SIM) in GC/MS and selected reaction monitoring (SRM) in LC-MS/MS, where only targeted ions are monitored, increase sensitivity but require prior knowledge of what compound is to be measured. LC-HR/MS offers mass assignment with an accuracy of 0.001 atomic mass units (amu) compared with 1 amu in conventional MS. Tentative identification is thus directed to a very limited set of compounds (or even one unique compound) based on the exact molecular formula rather than a fragmentation pattern, since HR/MS can discriminate between compounds with the same nominal molecular mass. LC-MS/MS has clear advantages over GC/MS in ease and speed of sample preparation and the opportunities for its automation. LC-HR/MS is more suitable to clinical toxicology because the drugs present in a sample are rarely known a priori, and tentative identifications of unknowns can be made without the availability of a reference standard or a library spectrum. Blood can be used in preference to urine which is more relevant to the patient's current clinical situation. Methods. A literature search was conducted using PUBMED for clinical toxicology, adulterants in illicit drugs and herbal supplements, and case reports using LC-TOF/MS and LC-HR/MS. Only 42 papers in English were identified in these searches. LC-HR/MS in clinical toxicology. LC-HR/MS has been used to detect designer drugs, doping agents, (neurosteroids) and adulterants such as levamisole, a veterinary antihelmitic found in street cocaine, and pharmaceuticals in herbal medications marketed to contain only natural ingredients. LC-HR/MS has proved useful for cases where existing tests were unable to identify the cause of the intoxication. One patient suffered a drug-induced seizure which was originally thought to be caused by an herbal medication, but diphenhydramine was determined to be the culprit. In another, 5-oxoproline was identified as the cause of metabolic acidosis seen in chronic acetaminophen (paracetamol) use. LC-HR/MS has successfully identified medications that were mislabeled or misrepresented street drugs. In one case, medications sold as diazepam were determined to be glyburide instead. The identification of novel designer amines, stimulants found in “bath salts”, and synthetic cannabinoids are well suited to LC-HR/MS. Dozens or even hundreds of possible compounds cannot realistically be tested on an individual basis by targeted LC-MS/MS or GC/MS analysis. Conclusions. LC-HR/MS offers unique opportunities for time-sensitive clinical analysis of blood samples from intoxicated patients and for comprehensive screening in a wide range of situations and materials. While the identification is not as definitive as that obtained by conventional fragmentation MS, the presumptive identification can be confirmed later with standards and spectral library matches. Optimum utilization of the presumptive diagnosis requires close collaboration between the laboratory analysts and their clinical counterparts.     

LC–MS/MS progress in newborn screening

Newborn screening programs detect treatable disorders in infants before they become symptomatic. Liquid chromatography-tandem mass spectrometry (LC–MS/MS) has greatly increased the screening possibilities by monitoring levels of amino acids and acylcarnitines. After the initial screening step, LC–MS/MS can also be used in screening positive samples as a second tier test to differentiate between true and false positive samples.As the list of disorders screened for by LC-tandem MS increases, questions arise about screening for untreatable disorders, such as some lysosomal storage diseases (LSDs). For LSDs screening methods are being developed and tested more quickly than treatments are becoming available. This goes against one of the main tenets of newborn screening which requires that a treatment be available.LC–MS/MS can detect several disorders with a single injection, which is important in high throughput laboratories. Measuring different amino acids and acylcarnitines can be used to detect up to 45 different inherited disorders depending on how diseases are counted. The LSD assays are designed in a similar way to detect multiple disorders with common sample preparation and a single injection. The clinical implications of applying this technology to NBS on a large scale in many jurisdictions across the world are discussed.     

Development,validation, and clinical application of an FIA‐MS/MS method for the quantification of lysophosphatidylcholines in dried blood spots

BackgroundLysophosphatidylcholine (LPC) plays pivotal roles in several physiological processes and their disturbances are closely associated with various disorders. In this study, we described the development and validation of a reliable and simple flow injection analysis–tandem mass spectrometry (FIA‐MS/MS)‐based method using dried blood spots (DBS) for quantification of four individual LPC (C20:0, C22:0, C24:0, and C26:0).MethodsLysophosphatidylcholines were extracted from 3.2 mm DBS with 85% methanol containing 60 ng/ml internal standard using a rapid (30 min) and simple procedure. The analytes and the internal standard were directly measured by triple quadrupole tandem mass spectrometry in multiple reactions monitoring mode via positive electrospray ionization.ResultsMethod validation results showed good linearity ranging from 50 to 2000 ng/ml for each LPC. Intra‐ and inter‐day precision and accuracy were within the acceptable limits at four quality control levels. Recovery was from 70.5% to 107.0%, and all analytes in DBS were stable under assay conditions (24 h at room temperature and 72 h in autosampler). The validated method was successfully applied to assessment of C20:0‐C26:0LPCs in 1900 Chinese neonates. C26:0‐LPC levels in this study were consistent with previously published values.ConclusionWe propose a simple FIA‐MS/MS method for analyzing C20:0‐C26:0LPCs in DBS, which can be used for first‐tier screening.     

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

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 CH(3)CN/H(2)O 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 micromol/L, respectively, for MMA and 8 and 10 micromol/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.     

Semi-automated quantification of methylmalonic acid in human serum by LC-MS/MS

Abstract Background. Methylmalonic acid (MMA), a sensitive biomarker of functional vitamin B12 deficiency, is commonly determined by gas chromatography-mass spectrometry (GC-MS) or liquid chromatography-tandem mass spectrometry (LC-MS/MS) methods using manual extraction and derivatization of MMA to reduce polarity prior to separation. Methods. In the present study we introduce a semi-automated extraction on a strong anion exchanger, HPLC separation on a BEH-amide column to separate serum MMA from its abundant isoform, succinic acid, followed by MS/MS detection and quantification. Results. The extraction of MMA plus internal standard provides full recovery and the method is linear between 0.03 μmol/L and 20.0 μmol/L (r(2) =?1.0) with intra-and inter-assay imprecision of 2.2%. Agreement with other laboratories has been demonstrated in external proficiency testing. Compared to both conventional GC-MS and LC-MS/MS methods, the correlation is r(2) >?0.99. Conclusions. The use of robotic pipetting, elimination of derivatization and improved separation by the BEH-amide column combined with HILIC chromatographic conditions significantly improve sample throughput compared to conventional methods. Using a single pipetting robot and LC-MS/MS instrument, this method is currently performing 180 analyses per day from10 regional hospitals and several additional distant sites.     

Analysis of methylmalonic acid in plasma by liquid chromatography-tandem mass spectrometry

BACKGROUND: Methylmalonic acid (MMA) is a biochemical marker for cobalamin deficiency, particularly in cases where the cobalamin concentration is moderately decreased or in the low-normal range. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) with electrospray ionization is a rapid, robust method that has been used in MMA analysis. We developed a simple method combining solid-phase extraction (SPE) and derivatization to prepare serum or plasma for LC-MS/MS analysis of MMA. METHODS: Deuterated internal standard d(3)-MMA was added to serum or plasma before SPE on strong anion-exchange (SAX) columns. After elution with HCl-butanol (10:90 by volume) and addition of 1 g/L formic acid, the samples were simultaneously derivatized and evaporated by heating to 70 degrees C for 15 min followed by 54 degrees C overnight in uncapped vials. Acetonitrile and 1 g/L formic acid were added to the samples before injection into the LC-MS/MS system. MMA and d(3)-MMA were quantified in the multiple-reaction monitoring mode. Calibrators were prepared in serum by the standard addition method. RESULTS: The MMA assay was linear up to 200 micromol/L. Interassay CVs were 6.7%, 5.0%, and 5.0% for mean concentrations of 0.15, 0.36, and 0.65 micromol/L, respectively. CONCLUSIONS: Our simplified sample preparation and derivatization method is suitable for use in MMA analyses. MMA elutes with the derivatization reagent, and derivatization and evaporation are performed simply by leaving the uncapped vials in a heating block overnight. The method shows good linearity and precision.     

Role of liquid chromatography-high-resolution mass spectrometry (LC-HR/MS) in clinical toxicology

Background. Gas chromatography (GC) and liquid chromatography (LC) coupled with mass spectrometry (MS) are widely used to confirm drug screening results and for urine screening in presumed intoxicated patients. These techniques are better suited to targeted analysis than to general unknown screening and, due to the complexity of testing, results are seldom available rapidly enough to contribute to the immediate care of the patient. High resolution (HR)/MS with time-of-flight (TOF) or orbitrap instruments offer potential advantages in clinical toxicology. Comparison of GC-MS, LC-MS/MS and LC-HR/MS. For unknown analyses, GC-MS and LC-MS/MS require comparison of full-scan spectra against preestablished libraries. Operation in full-scan mode greatly reduces sensitivity and some drugs present in low but significant concentrations may be missed. Selected ion monitoring (SIM) in GC/MS and selected reaction monitoring (SRM) in LC-MS/MS, where only targeted ions are monitored, increase sensitivity but require prior knowledge of what compound is to be measured. LC-HR/MS offers mass assignment with an accuracy of 0.001 atomic mass units (amu) compared with 1 amu in conventional MS. Tentative identification is thus directed to a very limited set of compounds (or even one unique compound) based on the exact molecular formula rather than a fragmentation pattern, since HR/MS can discriminate between compounds with the same nominal molecular mass. LC-MS/MS has clear advantages over GC/MS in ease and speed of sample preparation and the opportunities for its automation. LC-HR/MS is more suitable to clinical toxicology because the drugs present in a sample are rarely known a priori, and tentative identifications of unknowns can be made without the availability of a reference standard or a library spectrum. Blood can be used in preference to urine which is more relevant to the patient's current clinical situation. Methods. A literature search was conducted using PUBMED for clinical toxicology, adulterants in illicit drugs and herbal supplements, and case reports using LC-TOF/MS and LC-HR/MS. Only 42 papers in English were identified in these searches. LC-HR/MS in clinical toxicology. LC-HR/MS has been used to detect designer drugs, doping agents, (neurosteroids) and adulterants such as levamisole, a veterinary antihelmitic found in street cocaine, and pharmaceuticals in herbal medications marketed to contain only natural ingredients. LC-HR/MS has proved useful for cases where existing tests were unable to identify the cause of the intoxication. One patient suffered a drug-induced seizure which was originally thought to be caused by an herbal medication, but diphenhydramine was determined to be the culprit. In another, 5-oxoproline was identified as the cause of metabolic acidosis seen in chronic acetaminophen (paracetamol) use. LC-HR/MS has successfully identified medications that were mislabeled or misrepresented street drugs. In one case, medications sold as diazepam were determined to be glyburide instead. The identification of novel designer amines, stimulants found in "bath salts", and synthetic cannabinoids are well suited to LC-HR/MS. Dozens or even hundreds of possible compounds cannot realistically be tested on an individual basis by targeted LC-MS/MS or GC/MS analysis. Conclusions. LC-HR/MS offers unique opportunities for time-sensitive clinical analysis of blood samples from intoxicated patients and for comprehensive screening in a wide range of situations and materials. While the identification is not as definitive as that obtained by conventional fragmentation MS, the presumptive identification can be confirmed later with standards and spectral library matches. Optimum utilization of the presumptive diagnosis requires close collaboration between the laboratory analysts and their clinical counterparts.     

液相色谱串联质谱技术在载脂蛋白E室间质量评价中的应用

目的探讨液相色谱串联质谱技术(LC-MS/MS)在载脂蛋白E(apo E)室间质量评价中的应用。方法分别将5份混合人血清样品冷链运送到76家实验室,用免疫比浊法(ITA)进行单次检测。以同位素标记精氨酸的肽段为内标,对标本进行变性、烷基化和胰蛋白酶酶解处理,液相色谱部分采用SB-C18色谱柱分离,质谱部分采用正离子模式和多反应监测定量。JMP13.0软件分析不同方法分组所对应的相对偏倚。结果对于所有样品,ITA检测apo E的方法组内不精密度在1.7%至20.4%之间。总不精密度在8%左右(s B~s E样品)。5个样品相对偏倚的均值分别是(按照样品浓度由低到高排列):-34.2%、-9.4%、-9.8%、-2.7%和-2.1%。高浓度样品比低浓度样品更接近LC-MS/MS检测结果。结论 LC-MS/MS检测apo E可评价免疫法的准确性,为临床应用提供帮助。     

新生儿异戊酸血症串联质谱法与相关基因突变检测的价值研究

目的 了解福建省泉州地区新生儿异戊酸血症（isovaleric acidemia, IVA）串联质谱法与相关基因突变检测情况。方法 2019年1月～2020年12月,泉州地区共有151 917例新生儿进行串联质谱遗传代谢病筛查,异戊酰基肉碱(isovalerylcarnitine, AISO-C5)浓度升高的筛查样本应用MassARRAY技术进行IVD基因突变筛查,IVA疑似样本采用高通量测序技术诊断。结果 研究期间共有132例新生儿表现为浓度升高,采用传统筛查规则需召回132例新生儿,召回复查阳性人数20例,1例确诊为IVA患者,IVA的阳性预测值为0.76%。此外,3例新生儿被诊断为2-甲基丁酰辅酶A脱氢酶缺乏症（2-methylbutyryl-CoA dehydrogenase deficiency,2-MBAD）患者。联合应用基因突变筛查后,仅5例新生儿结果异常,基因诊断证实4例新生儿为IVA携带者,1例新生儿为IVA患者,因此IVA的阳性预测值提高至20%。所有患者的新生儿筛查和召回复查结果均显示AISO-C5浓度升高。1例IVA患者携带IVD基因c.499A> G(p...     

Postnatal variations in blood free and acylcarnitines

Background: Alteration in concentrations of blood carnitine and its esters are diagnostic of a number of inherited metabolic disorders. Acylcarnitine (AC) profiles of newborns obtained from dried blood spots by tandem mass spectrometric analysis are being used for the diagnosis of these disorders. There are no data of the postnatal variations of free carnitine (FC) and AC in Indian neonates. Objectives: Evaluation of postnatal variations in free and AC levels in newborns. Methods: Blood FC and AC levels were evaluated in 2,727 healthy neonates of postnatal day 2–30 by electrospray ionization tandem mass spectrometry. Results: Blood C2, C5DC, C16, C16:1, C18, C18:1, C18:2, and C18:OH carnitineswere increased in groups A (aged 8–14 days) and B (aged 15–30 days), compared with the control group (aged 2–7 days), whereas C3, C4, C4OH, C6, C6DC, and C12 carnitines were increased only in group B. No sex‐related differences were found except for C3DC, C4, and C5 carnitine concentrations, which were higher in female neonates. Conclusions: Our data can be used as a reference for the assessment of carnitine status in Indian newborns, hence reducing the risk of misdiagnosis of fatty acid oxidation disorders and organic acidemias during interpretation of the results of tandem mass spectrometry‐based newborn screening. J. Clin. Lab. Anal. 25:126–129, 2011. © 2011 Wiley‐Liss, Inc.