Livestock and companion animal health have a direct impact on human health. Research on clinical laboratory technology for veterinary medicine is as important as that on human laboratory technology. Reagents and analysis equipment for human medical laboratory tests are often used in veterinary medicine. Medical laboratories in Japan utilize the Japan Society of Clinical Chemistry (JSCC) method for blood alkaline phosphatase (ALP) analysis. The International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) method is used worldwide for ALP catalytic concentration measurement. When the IFCC method is used, human blood ALP activity is approximately one-third of the JSCC method’s activity. The JSCC method for ALP measurement was switched to the IFCC method in medical laboratories in Japan in April 2020 for global standardization purpose. It is uncertain whether conventional JSCC method reagents will continue to be supplied. In veterinary medicine, the relationship between the JSCC and IFCC methods in terms of ALP measurement is almost unclear. This study investigated the regression between JSCC and IFCC methods measuring ALP in bovine, canine, feline, and human. The regression formulas for bovine, canine, feline, and human ALP values using the conventional JSCC (x) and IFCC (y) methods arey= 0.379x+ 0.124,y= 0.289x+ 8.291,y= 0.358x+ 0.432, andy= 0.337x+ 2.959, respectively. These results suggested that the IFCC method measurement could be estimated by approximately one-third of the JSCC method measurement in animal species such as bovine, canine, and feline. By applying the conversion factors proposed in this study, a very good correlation could be obtained between the two methods for each animal.

Since April 2020, the method for lactate dehydrogenase (LD) and alkaline phosphatase (ALP) activity measurements in Japan has been switched from the Japan Society of Clinical Chemistry (JSCC) reference method, which is only used in Japan, to the International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) reference method. However, in some species, the relationship between the blood values of both enzymes measured by the two methods remains unclear. Hence, values measured by these two methods cannot be used interchangeably. Therefore, this relationship was examined in ICR mice and Wistar/ST rats. The LD and ALP values obtained by both methods were plotted on scatter graphs, and regression equations were obtained. To compare the JSCC (x) and IFCC (y) methods, regression equations were generated for LD values in non-hemolytic samples as follows: y = 0.954x − 4.008 for ICR mice and y = 0.963x − 6.324 for Wistar/ST rats. The conversion factors from the JSCC to the IFCC methods were 0.954 (mice) and 0.963 (rats). The conversion coefficients from the IFCC to the JSCC methods were 1.048 (mice) and 1.088 (rats). For ALP values in fasted mouse and rat samples, the regression equations were y = 0.336x − 2.247 and y = 0.314x − 17.626, respectively. The conversion factors from the JSCC to the IFCC methods were 0.336 (mice) and 0.314 (rats). The conversion coefficients from the IFCC to the JSCC methods were 2.978 (mice) and 3.188 (rats). These conversion factors can be used for the mutual conversion of both measured values during the transition period from the JSCC to the IFCC method. However, it should be noted that the conversion coefficients for both LD and ALP were affected by isozyme composition.

Seaweeds contain large amounts of organoarsenic compounds, mostly arsenosugars (AsSug) and arsenolipids (AsLipid). AsSug is mainly metabolized into dimethylarsinic acid (DMA ^V ) in humans. However, this metabolic process is not well understood. We investigated the metabolism of an AsSug, 3-[5'-deoxy-5'-(dimethylarsinoyl)-β-ribofuranosyloxy]-2-hydroxypropylene glycol (AsSug328), in the gastrointestinal tract using an in vitro artificial gastrointestinal digestion system. AsSug328 was incubated with gastric juice for 4 h, with bile-pancreatic juice for 0.5 h, and finally with enteric bacteria solution for 24 h. The conversion of arsenic compounds after artificial digestion was analyzed by HPLC-ICP-MS and HPLC-ESI-Q-TOF-MS. Our results show that artificial gastrointestinal digestion converted AsSug328 into thio-AsSug328. However, no formation of DMA ^V was detected. Under the artificial digestion system, the 5-deoxyribofuranose structure of AsSug was maintained. Therefore, AsSug should be absorbed in the intestinal tract after its sugar moiety is partially decomposed. They are then possibly metabolized to DMA ^V in the liver and subsequently excreted through urine.

Two methods of measuring triacylglycerol (TG) in the blood are used in clinical laboratories. The glycerol-blanked TG analysis method is used primarily in Japan; the total glyceride measurement method is used in most countries, including the United States. The latter method includes free glycerol in the blood, which is known to be slightly higher in humans. However, the extent to which the 2 methods differ in companion animals is unknown. We used cryopreserved blood from dogs and cats that visited a secondary veterinary hospital to investigate the relationship between the data obtained using the 2 TG analysis methods. The median ratio (5th and 95th percentiles) of total glyceride measurement:glycerol-blanked TG measurement ratios was 1.24 (1.08 and 1.77) for dogs and 2.00 (1.44 and 3.66) for cats, with the total glycerol method clearly having higher values. The Passing–Bablok regression equation comparing the total glyceride method (y) and glycerol-blanked method (x) was y = 1.049x + 0.119 for dogs and y = 1.476x + 0.177 for cats. The estimated free glycerol value calculated from the difference between the 2 TG measurements was strongly correlated with the measured free glycerol value (dog, r = 0.7905; cat, r = 0.8708), indicating that free glycerol in the blood was the cause of the TG measurement discrepancy. Therefore, the TG concentrations obtained from total glyceride assays in dogs and cats may contain non-negligible levels of free glycerol.

C-reactive protein (CRP) is a key biomarker for diagnosis and prognosis in dogs. Accurate and consistent CRP measurements are essential for clinical decision-making. In Japan, different CRP measurement systems are commonly used, but their compatibility has not been validated. In this study, we evaluated the correlation and agreement among three CRP assay systems (immunonephelometry, immunoturbidimetry, and dry chemistry) using 138 dog plasma samples. Strong correlations (r>0.9) were observed, but regression analysis and Bland-Altman plots revealed systematic errors, indicating that these systems are not interchangeable. These findings highlight the need for system-specific reference ranges and clinical decision thresholds and suggest that a common calibration agent could enhance comparability and support the standardization of CRP measurements in veterinary medicine.

We investigated the analytical performance and robustness of a flow-type immunosensor (FIS)-based canine C-reactive protein (CRP) measurement system against analytical interferents. To improve the clinical applicability of the canine FIS CRP measurement system, we reduced the measurement time to 9 min. Statistical analyses, including scatter plots, Bland–Altman plots, and Passing–Bablok regression analyses, were performed to evaluate agreement with a comparative method (particle-enhanced turbidimetric immunoassay). Within-run imprecision (10 replicates) was 8.2% and 6.4% at ~39 and 115 mg/L; between-run imprecision (20 measurement days) was 9.9% and 6.5% at ~39 and 115 mg/L, respectively. The lower limit of quantification in the FIS measurement system was 4.0 mg/L, and quantification linearity was confirmed from 4.0 to 300 mg/L. CRP content was measured in canine heparinized plasma samples ( n = 43) using both the comparative method (x) and the FIS (y). The regression equation for our new method (y) as a function of the reference method (x) was y = 0.979x + 0.592 ( R ² = 0.974). The system was robust against typical interfering components, including hemoglobin, lipids, and bilirubin. The FIS method was not suitable for K ₂ EDTA plasma. Based on between-run imprecision (20 measurement days) and concentration-specific targeted bias derived from Passing–Bablok regression, the observed total error was 20.3% and 14.6% at ~39 and 115 mg/L, respectively, meeting the American Society for Veterinary Clinical Pathology desirable and minimum performance goals, as well as optimal performance at the higher concentration level.