Suitability of capillary blood obtained by a minimally invasive lancet technique to detect subclinical ketosis in dairy cows by using 3 different electronic hand-held devices

Abstract

The objective of this study was to evaluate the suitability of capillary blood obtained by a minimally invasive lancet technique to detect subclinical ketosis in 49 prepartum and 191 postpartum Holstein-Friesian cows using 3 different electronic hand-held devices [FreeStyle Precision (FSP, Abbott), GlucoMen LX Plus (GLX, A. Menarini), NovaVet (NOV, Nova Biomedical)]. The β-hydroxybutyrate (BHBA) concentration in serum harvested from coccygeal blood samples was analyzed in a laboratory and used as a reference value. Capillary samples were obtained from the skin of the exterior vulva by using 1 of 3 different lancets. In all samples, the concentration of BHBA was immediately analyzed with all 3 hand-held devices used in random order. All lancets used in the study were eligible for capillary blood collection but differed in the total number of incisions needed. Spearman correlation coefficients between the BHBA concentrations in capillary blood and the reference test were highly significant with 83% for the FSP, 73% for the NOV, and 63% for the GLX. Using capillary blood, the FSP overestimated the mean BHBA concentration compared with the reference test (+0.08 mmol/L), whereas the GLX and NOV underestimated the mean concentration (-0.07 and -0.01 mmol/L). When a BHBA concentration of 1.2 mmol/L in serum was used to define subclinical ketosis, the corresponding analyses of receiver operating characteristics resulted in optimized thresholds for capillary blood of 1.1 mmol/L for the NOV and GLX devices, and of 1.0 mmol/L for the FSP. Based on these thresholds, sensitivities (Se) and specificities (Sp) were 89 and 84% for the NOV, 80 and 89% for the GLX, and 100 and 76% for the FSP. Based on a serum BHBA concentration of 1.4 mmol/L, analyses of receiver operating characteristics resulted in optimized cut-offs of 1.4 mmol/L for the FSP (Se 100%, Sp 92%), 1.3 mmol/L for the NOV (Se 80%, Sp 95%), and 1.1 mmol/L (Se 90%, Sp 85%) for the GLX. Using these optimized thresholds for the specific hand-held meters, no significant differences between the devices in Se and Sp to detect subclinical ketosis in coccygeal blood were observed. Calculated test characteristics for analyzing capillary blood using the hand-held devices were numerically smaller compared with blood obtained from a coccygeal vessel, but overlapping confidence intervals indicate no statistical difference between the origin of the sample. Hence, this procedure seems to be suitable for ketosis monitoring in dairy cows, but further validation with more data from different farms is recommended.

Measurement of β-hydroxybutyrate in capillary blood obtained from an ear to detect hyperketonemia in dairy cows by using an electronic handheld device

“…The previously reported average inter-and intra-assay coefficients of variations for another handheld meter, the FreeStyle Precision device, were 7.2 and 7.9% for capillary blood from the skin of the exterior vulva (Kanz et al, 2015), and 5.8 and 5.7% for whole blood from a tail vessel (Iwersen et al, 2013). The measurements from capillary blood at the ear yielded similar average inter-and intra-assay coefficients of variation of 2.6 and 11.7%, respectively.…”

“…With this threshold, the results from ROC analyses for capillary blood were excellent; overall accuracies were AUROC ≥90% with a Se of 100% for all 3 sampling locations and a Sp of at least 93%. Kanz et al (2015) evaluated the use of different handheld meters for BHB testing in capillary blood obtained from the skin of the exterior vulva. For the FreeStyle Precision and the NovaVet device, similar ρ s = 83% and 73% with lower mean ± standard deviation BHB differences of 0.08 ± 0.19 mmol/L and −0.01 ± 0.43 mmol/L, respectively, were described.…”

“…Kanz et al (2015) tested the suitability of capillary blood obtained from the skin of the external vulva for BHB measurements using different handheld devices in dairy cows. The authors reported that this technique is eligible to detect SCK.…”

A 100-Year Review: Metabolic health indicators and management of dairy cattle

“…Work from Mahrt et al (2014) showed that blood samples can be collected at any time of day for precise measurement of BHB concentration in continuously fed dairy cows; however, the jugular vein or coccygeal vessels should be used for blood collection because blood BHB concentrations in the mammary vein are quite a bit lower. Other European colleagues (Kanz et al, 2015;Süss et al, 2016) have found that capillary measurement of blood BHB concentrations using a lancet device in the skin of the exterior vulva or ear is an acceptable and minimally invasive method for classifying cows with hyperketonemia.…”

Point‐of‐care testing in cattle practice: reliability of cow‐side diagnostic tests

“…This is easily taken from the coccygealvessels using a 20 or 18G needle, although capillary blood obtained by the minimally invasive lancet puncture is also valid (Kanz and others 2015). In our experience, using just a needle in the coccygeal vein or artery can produce a stream of blood that stains the meter (remember that the strip has to be connected to the meter before the blood is applied), so to prevent this, we usually connect the needle to a small syringe and then carefully dispense a drop of blood onto the strip (Fig d).…”