Comparison of measurement methods for carboxyhemoglobin in blood samples based on visible spectra with 17 institutions

• Published in: Forensic toxicology Vol. 37; no. 2; pp. 330 - 338
• Main Authors: Ohmori, Takeshi, Saito, Yusuke, Mamiya, Kou, Sasaoka, Sara, Suzuki, Yasuhito, Namekawa, Yoshimasa, Otsuka, Kazunori, Kogure, Seiichi, Mochizuki, Akira, Nomura, Yosuke, Asaoka, Kazuyo, Saito, Takaoki, Yoshida, Kazuyuki, Ojima, Masaki, Koizumi, Takako, Kumihashi, Mitsuru, Shimada, Hiroshi, Wakita, Seiya, Otsuka, Mai, Seto, Yasuo
• Format: Journal Article
• Language: English
• Published: Singapore Springer Singapore 01-07-2019
• Subjects: Forensic Medicine; Forensic Science; Medical Law; Medicinal Chemistry; Medicine; Medicine & Public Health; Original Article; Pharmacology/Toxicology; Spectrometric; Gas chromatography; Carboxyhemoglobin; Carbon monoxide; Blood
• ISSN: 1860-8965; 1860-8973
• DOI: 10.1007/s11419-019-00469-y

Purpose
An inter-method variation experiment to evaluate visible spectrophotometric methods for determining carboxyhemoglobin (CO-Hb) in blood was performed in 17 different forensic science laboratories.
Methods
Three reference samples were prepared and the actual percentages of CO-Hb (%CO-Hb) in reference samples were determined with gas chromatography. The %CO-Hb values in reference samples were measured via four procedures: (1) the “Standard method of chemical analysis in poisoning 2017” (edited by the Pharmaceutical Society of Japan), (2) the isosbestic point method (developed by the Department of Forensic Medicine, Kagawa University), (3) the alkaline condition method, and (4) ISO 27368 with a slight modification.
Results
Procedures (
1
) and (2) gave results approximately the same as the actual values in low-%CO-Hb samples, but both methods underestimated %CO-Hb levels in blood samples with high %CO-Hb. Using a formula reported by Katsumata et al., procedure (3) overestimated %CO-Hb levels in blood samples with low %CO-Hb, while using the modified formula, gave underestimates in all samples. Procedure (4) gave %CO-Hb values relatively close to the actual values. Thus, an accuracy evaluation test was performed for this procedure and the values obtained were close to the actual CO-Hb content levels.
Conclusions
Procedure (4) was considered sufficiently accurate and thus recommendable for use in forensic science laboratories.