Evaluation of 2 portable ion-selective electrode meters for determining whole blood, plasma, urine, milk, and abomasal fluid potassium concentrations in dairy cattle

Abstract

Two low-cost ion-selective electrode (ISE) handheld meters (CARDY C-131, LAQUAtwin B-731; Horiba Ltd., Albany, NY) have recently become available for measuring the potassium concentration ([K(+)]) in biological fluids. The primary objective of this study was to characterize the analytical performance of the ISE meters in measuring [K(+)] in bovine whole blood, plasma, urine, milk, and abomasal fluid. We completed 6 method comparison studies using 369 whole blood and plasma samples from 106 healthy periparturient Holstein-Friesian cows, 138 plasma samples from 27 periparturient Holstein-Friesian cows, 92 milk samples and 204 urine samples from 16 lactating Holstein-Friesian cows, and 94 abomasal fluid samples from 6 male Holstein-Friesian calves. Deming regression and Bland-Altman plots were used to characterize meter performance against reference methods (indirect ISE, Hitachi 911 and 917; inductively coupled plasma-optical emission spectroscopy). The CARDY ISE meter applied directly in plasma measured [K(+)] as being 7.3% lower than the indirect ISE reference method, consistent with the recommended adjustment of +7.5% when indirect ISE methods are used to analyze plasma. The LAQUAtwin ISE meter run in direct mode measured fat-free milk [K(+)] as being 3.6% lower than the indirect ISE reference method, consistent with a herd milk protein percentage of 3.4%. The LAQUAtwin ISE meter accurately measured abomasal fluid [K(+)] compared to the indirect ISE reference method. The LAQUAtwin ISE meter accurately measured urine [K(+)] compared to the indirect ISE reference method, but the median measured value for urine [K(+)] was 83% of the true value measured by inductively coupled plasma-optical emission spectroscopy. We conclude that the CARDY and LAQUAtwin ISE meters are practical, low-cost, rapid, accurate point-of-care instruments suitable for measuring [K(+)] in whole blood, plasma, milk, and abomasal fluid samples from cattle. Ion-selective electrode methodology is not suitable for measuring [K(+)] in bovine urine.

Characterization of the analytic performance of an electrochemical point‐of‐care meter for measuring β‐hydroxybutyrate concentration in blood and plasma from periparturient dairy cattle

“…Further results have been published elsewhere. [39][40][41][42] Immediately after blood collection, BHB was measured in a drop of nonheparinized blood from the tip of the vacutainer needle using an electronic hand-held meter (Precision Xtra; Blood Glucose and Ketone Monitoring System; Abbott Diabetes Care Inc., Alameda, CA, USA). Both coded ketone test strips that included a calibrator strip with each new box of test strips, and noncoded ketone test strips were used.…”

Evaluation of hand‐held sodium, potassium, calcium, and electrical conductivity meters for diagnosing subclinical mastitis and intramammary infection in dairy cattle

“…The low‐cost (approximately $250 US) and portability of the meters, as well as their ability to measure cation concentrations or EC in uncentrifuged milk samples, make them very attractive for on‐farm or cow‐side use. Studies conducted by our laboratory over the past 5 years have validated the accuracy of Na and K LAQUAtwin meters in measuring unbound Na and K concentrations in bovine cisternal milk . The Ca LAQUAtwin meter has been used to measure ionized Ca concentration in bovine milk .…”

Acute coumaphos organophosphate exposure in the domestic dogs: Its implication on haematology and liver functions

“…Plasma aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), and lipid profile including total cholesterol (TC), triglyceride (TAG), high-density lipoprotein (HDL), and low-density lipoprotein (LDL) were determined using Randox assay kits, Randox Diagnostics, Crumlin, United Kingdom. Plasma electrolytes including; sodium, potassium, chloride, and bicarbonate were determined by potentiometry method at 8, 24 and 36 hrs after exposure [16] .…”