A Simple Flow Injection Analysis–Tandem Mass Spectrometry Method to Reduce False Positives of C5-Acylcarnitines Due to Pivaloylcarnitine Using Reference Ions
Flow injection analysis–tandem mass spectrometry (FIA-TMS) has been applied in a first-tier test of newborn screening (NBS). Although isovalerylcarnitine (i-C5), which is a diagnostic indicator of isovaleric acidemia (IVA), is isobaric with pivaloylcarnitine (p-C5), 2-methylbutyrylcarnitine, and n-v...
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| Language: | English |
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MDPI AG
2022-05-01
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| Series: | Children |
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| Online Access: | https://www.mdpi.com/2227-9067/9/5/694 |
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| author | Takanari Hattori Yoshitomo Notsu Misa Tanaka Miki Matsui Tetsuo Iida Jun Watanabe Yoshimitsu Osawa Seiji Yamaguchi Shozo Yano Takeshi Taketani Hironori Kobayashi |
| author_facet | Takanari Hattori Yoshitomo Notsu Misa Tanaka Miki Matsui Tetsuo Iida Jun Watanabe Yoshimitsu Osawa Seiji Yamaguchi Shozo Yano Takeshi Taketani Hironori Kobayashi |
| author_sort | Takanari Hattori |
| collection | DOAJ |
| description | Flow injection analysis–tandem mass spectrometry (FIA-TMS) has been applied in a first-tier test of newborn screening (NBS). Although isovalerylcarnitine (i-C5), which is a diagnostic indicator of isovaleric acidemia (IVA), is isobaric with pivaloylcarnitine (p-C5), 2-methylbutyrylcarnitine, and n-valerylcarnitine, these isomers cannot be distinguished by the FIA-TMS. There are many reports of false positives derived from p-C5 due to the use of pivalate-conjugated antibiotics. In this study, we developed a new FIA-TMS method to distinguish i-C5 and p-C5. We found that the intensity ratio of product ions for i-C5 and p-C5 was different in a certain range even under the same analytical conditions. The product ions with the most distinct differences in ionic intensity between the isomers and the collision energies that produce them were determined to be <i>m/z</i> 246.2 > 187.1 and −15 V, respectively. In addition to the quantification ion, a reference ion was defined, and the similarity of the i-C5 and p-C5 reference ion ratios (i-C5 score and p-C5 score, respectively) were used to estimate which isomer (i-C5 and p-C5) was responsible for elevated C5 acylcarnitine in dried blood spots (DBSs). As a result of analyses of 11 DBS samples derived from pivalate-conjugated antibiotics and four DBS samples from IVA patients using our method, it was found that our method was able to correctly determine the type of C5-acylcarnitine (i-C5 or p-C5) in the DBS samples. Implementation of this new FIA-TMS method into the current NBS protocol will allow for a reduction in false positives in IVA. |
| first_indexed | 2024-03-10T03:09:07Z |
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| institution | Directory Open Access Journal |
| issn | 2227-9067 |
| language | English |
| last_indexed | 2024-03-10T03:09:07Z |
| publishDate | 2022-05-01 |
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| series | Children |
| spelling | doaj.art-d6852a94f40043b7ad2bbcf79dea09722023-11-23T10:31:02ZengMDPI AGChildren2227-90672022-05-019569410.3390/children9050694A Simple Flow Injection Analysis–Tandem Mass Spectrometry Method to Reduce False Positives of C5-Acylcarnitines Due to Pivaloylcarnitine Using Reference IonsTakanari Hattori0Yoshitomo Notsu1Misa Tanaka2Miki Matsui3Tetsuo Iida4Jun Watanabe5Yoshimitsu Osawa6Seiji Yamaguchi7Shozo Yano8Takeshi Taketani9Hironori Kobayashi10Shimadzu Corporation, Kyoto 604-8511, JapanLaboratories Division, Shimane University Hospital, Izumo 693-8501, JapanDepartment of Pediatrics, Faculty of Medicine, Shimane University, Izumo 693-8501, JapanDepartment of Pediatrics, Faculty of Medicine, Shimane University, Izumo 693-8501, JapanShimadzu Corporation, Kyoto 604-8511, JapanShimadzu Corporation, Kyoto 604-8511, JapanDepartment of Pediatrics, Faculty of Medicine, Shimane University, Izumo 693-8501, JapanDepartment of Pediatrics, Faculty of Medicine, Shimane University, Izumo 693-8501, JapanLaboratories Division, Shimane University Hospital, Izumo 693-8501, JapanDepartment of Pediatrics, Faculty of Medicine, Shimane University, Izumo 693-8501, JapanLaboratories Division, Shimane University Hospital, Izumo 693-8501, JapanFlow injection analysis–tandem mass spectrometry (FIA-TMS) has been applied in a first-tier test of newborn screening (NBS). Although isovalerylcarnitine (i-C5), which is a diagnostic indicator of isovaleric acidemia (IVA), is isobaric with pivaloylcarnitine (p-C5), 2-methylbutyrylcarnitine, and n-valerylcarnitine, these isomers cannot be distinguished by the FIA-TMS. There are many reports of false positives derived from p-C5 due to the use of pivalate-conjugated antibiotics. In this study, we developed a new FIA-TMS method to distinguish i-C5 and p-C5. We found that the intensity ratio of product ions for i-C5 and p-C5 was different in a certain range even under the same analytical conditions. The product ions with the most distinct differences in ionic intensity between the isomers and the collision energies that produce them were determined to be <i>m/z</i> 246.2 > 187.1 and −15 V, respectively. In addition to the quantification ion, a reference ion was defined, and the similarity of the i-C5 and p-C5 reference ion ratios (i-C5 score and p-C5 score, respectively) were used to estimate which isomer (i-C5 and p-C5) was responsible for elevated C5 acylcarnitine in dried blood spots (DBSs). As a result of analyses of 11 DBS samples derived from pivalate-conjugated antibiotics and four DBS samples from IVA patients using our method, it was found that our method was able to correctly determine the type of C5-acylcarnitine (i-C5 or p-C5) in the DBS samples. Implementation of this new FIA-TMS method into the current NBS protocol will allow for a reduction in false positives in IVA.https://www.mdpi.com/2227-9067/9/5/694isovaleric acidemianewborn screeningfalse positiveC5-acylcarnitineisovalerylcarnitinepivaloylcarnitine |
| spellingShingle | Takanari Hattori Yoshitomo Notsu Misa Tanaka Miki Matsui Tetsuo Iida Jun Watanabe Yoshimitsu Osawa Seiji Yamaguchi Shozo Yano Takeshi Taketani Hironori Kobayashi A Simple Flow Injection Analysis–Tandem Mass Spectrometry Method to Reduce False Positives of C5-Acylcarnitines Due to Pivaloylcarnitine Using Reference Ions Children isovaleric acidemia newborn screening false positive C5-acylcarnitine isovalerylcarnitine pivaloylcarnitine |
| title | A Simple Flow Injection Analysis–Tandem Mass Spectrometry Method to Reduce False Positives of C5-Acylcarnitines Due to Pivaloylcarnitine Using Reference Ions |
| title_full | A Simple Flow Injection Analysis–Tandem Mass Spectrometry Method to Reduce False Positives of C5-Acylcarnitines Due to Pivaloylcarnitine Using Reference Ions |
| title_fullStr | A Simple Flow Injection Analysis–Tandem Mass Spectrometry Method to Reduce False Positives of C5-Acylcarnitines Due to Pivaloylcarnitine Using Reference Ions |
| title_full_unstemmed | A Simple Flow Injection Analysis–Tandem Mass Spectrometry Method to Reduce False Positives of C5-Acylcarnitines Due to Pivaloylcarnitine Using Reference Ions |
| title_short | A Simple Flow Injection Analysis–Tandem Mass Spectrometry Method to Reduce False Positives of C5-Acylcarnitines Due to Pivaloylcarnitine Using Reference Ions |
| title_sort | simple flow injection analysis tandem mass spectrometry method to reduce false positives of c5 acylcarnitines due to pivaloylcarnitine using reference ions |
| topic | isovaleric acidemia newborn screening false positive C5-acylcarnitine isovalerylcarnitine pivaloylcarnitine |
| url | https://www.mdpi.com/2227-9067/9/5/694 |
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