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Tytuł:
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Air contamination of therapeutic drug monitoring assay reagents results in falsely high plasma ammonia levels.
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Autorzy:
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Tsukushi T; Department of Clinical Laboratory, 73444Kitasato University Hospital, Sagamihara, Japan.; Department of Clinical Chemistry, School of Allied Health Sciences, 89285Kitasato University, Sagamihara, Japan.
Shinohara R; Department of Clinical Laboratory, 73444Kitasato University Hospital, Sagamihara, Japan.
Adachi Y; Department of Clinical Laboratory, 73444Kitasato University Hospital, Sagamihara, Japan.
Kurosaki Y; Department of Clinical Chemistry, School of Allied Health Sciences, 89285Kitasato University, Sagamihara, Japan.
Ishii N; Department of Clinical Chemistry, School of Allied Health Sciences, 89285Kitasato University, Sagamihara, Japan.
Katagiri M; Department of Clinical Chemistry, School of Allied Health Sciences, 89285Kitasato University, Sagamihara, Japan.
Munekata S; Department of Clinical Laboratory, 73444Kitasato University Hospital, Sagamihara, Japan.
Kanoh Y; Department of Clinical Laboratory, 73444Kitasato University Hospital, Sagamihara, Japan.; Department of Laboratory Medicine, 38088Kitasato University School of Medicine, Sagamihara, Japan.
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Źródło:
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Annals of clinical biochemistry [Ann Clin Biochem] 2022 May; Vol. 59 (3), pp. 193-198. Date of Electronic Publication: 2022 Feb 08.
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Typ publikacji:
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Journal Article
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Język:
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English
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Imprint Name(s):
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Publication: Jan. 2013- : London : Sage
Original Publication: London, Association of Clinical Biochemists.
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MeSH Terms:
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Ammonia*
Drug Monitoring*
Humans ; Indicators and Reagents ; Quality Control ; Water
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Contributed Indexing:
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Keywords: Blood ammonia; air contamination; enzymatic assay; false positive
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Substance Nomenclature:
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0 (Indicators and Reagents)
059QF0KO0R (Water)
7664-41-7 (Ammonia)
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Entry Date(s):
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Date Created: 20220119 Date Completed: 20220425 Latest Revision: 20220531
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Update Code:
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20240105
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DOI:
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10.1177/00045632221074508
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PMID:
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35044236
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Background: Accumulating evidence shows that contamination of blood samples by atmospheric ammonia affects blood ammonia test levels; however, reports on the effect of ammonia contamination of assay reagents are limited. Here, we aimed to clarify the effect of ammonia contamination of assay reagents, particularly the therapeutic drug monitoring (TDM) reagents, on the detection levels of blood ammonia using enzymatic assays.
Methods: Ammonia gas was measured in the refrigerator compartment of the automatic analyser and the reaction tank water, probe wash water and drain outlets connected to the automatic analyser. At different time points following the closure of the cold storage, ammonia levels in quality control plasma samples were measured using three commercial assay reagents to evaluate the effect of air contamination. The distribution of evaporated ammonia in the reagent was measured using the CicaLiquid NH3 assay kit containing the assay reagent most affected by air contamination.
Results: It was confirmed that ammonia gas was generated in the cold storage of the automatic analyser. More than half of the reagents detected >0.25 ppm ammonia, and the highest concentration was detected in the TDM reagent. The ammonia levels obtained using all three reagents increased significantly after 3 h of air contamination. The effect was resolved by measuring a 'dummy' sample or mixing the reagents by inversion.
Conclusions: We demonstrated that air contamination by TDM reagents placed in cold storage could result in significantly falsely high ammonia measurements. Preventing this effect would improve the accuracy of ammonia measurements.
