Evidence map›Paper›PMID 39190263›Full record

ArticleForensic toxicology2025

Development of a simple estimation method of serum caffeine concentration using a point-of-care test kit for urinary caffeine.

Kenji Tsujikawa, Yuki Okada, Hiroki Segawa, Tadashi Yamamuro, Kenji Kuwayama, Tatsuyuki Kanamori, Yuko T Iwata

Abstract read
In one paragraph

Article in Forensic toxicology, 2025. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

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1 · What the graph read from it

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2 · The registry

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3 · Its place in the literature

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4 · The record

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5 · Who and what money

Authors and funding

7 authors.

Kenji TsujikawaNational Research Institute of Police Science, 6-3-1 Kashiwanoha, Kashiwa, Chiba, 277-0882, Japan. tujikawa@nrips.go.jp.ORCID 0000-0003-1380-9565
Yuki OkadaNational Research Institute of Police Science, 6-3-1 Kashiwanoha, Kashiwa, Chiba, 277-0882, Japan.
Hiroki SegawaNational Research Institute of Police Science, 6-3-1 Kashiwanoha, Kashiwa, Chiba, 277-0882, Japan.
Tadashi YamamuroNational Research Institute of Police Science, 6-3-1 Kashiwanoha, Kashiwa, Chiba, 277-0882, Japan.
Kenji KuwayamaNational Research Institute of Police Science, 6-3-1 Kashiwanoha, Kashiwa, Chiba, 277-0882, Japan.
Tatsuyuki KanamoriNational Research Institute of Police Science, 6-3-1 Kashiwanoha, Kashiwa, Chiba, 277-0882, Japan.
Yuko T IwataNational Research Institute of Police Science, 6-3-1 Kashiwanoha, Kashiwa, Chiba, 277-0882, Japan.

Funding

Japan Society for the Promotion of Science 20K09299
6 · The paper itself

Abstract

purposeSerum caffeine concentration is an indicator of caffeine intoxication; however, it is difficult to measure it in most emergency departments. We developed a simple estimation method using a point-of-care test kit for urinary caffeine.

methodsCaffeine-spiked human serum (100, 50, 25, and 10 µg/mL) was diluted 10-, 20-, 50-, and 100-fold with phosphate-buffered saline and applied to the kit. After 5 min incubation, the kit was scanned by a flatbed scanner and the membrane image was processed with ImageJ.

resultsWhen the 20-fold diluted serum was applied, serum samples with initial caffeine concentration ≤ 25 and ≥ 50 µg/mL were caffeine-negative and -positive, respectively. When the 100-fold diluted serum was applied, none of the caffeine-spiked serum samples gave positive results. Therefore, we proposed the following test procedure: (i) 20-fold diluted serum was initially tested and (ii) 100-fold diluted serum was additionally tested when the initial result was caffeine positive. Using this procedure, caffeine concentration is expected to be classified into three levels: ≤ 25, > 25- ≤ 100, and > 100 µg/mL, which almost correspond to no or mild, severe, and potentially fatal intoxication, respectively. The test procedure was validated using postmortem heart blood from two cases of fatal caffeine intoxication (caffeine concentration: 276 and 175 µg/mL) and two cases of other intoxication.

conclusionsOur developed method using point-of-care urinary caffeine test kits enabled simple estimation of serum caffeine concentration.

Indexed as

CaffeineCentral Nervous System StimulantsPoint-of-Care SystemsSubstance Abuse DetectionHumansCaffeineCentral Nervous System StimulantsCaffeineFlatbed scannerImageJPoint-of-care test kitSerum concentration

Identifiers

PMID39190263
PMCPMC11782425

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.