# Comparison of glucose concentration measured in samples collected with different anticoagulants and analyzed using 2 glucose quantification methods

## TL;DR

This study compares how different anticoagulants and glucose measurement methods affect glucose concentration readings in cow blood samples.

## Contribution

The study identifies that K2-EDTA and Li-Hep anticoagulants can be used for glucose quantification as alternatives to NaF, though with higher readings.

## Key findings

- Samples collected in NaF tubes had lower glucose concentrations compared to K2-EDTA and Li-Hep tubes.
- Glucose concentrations measured with the HK method were lower than those measured with the PGO method.
- Using K2-EDTA or Li-Hep anticoagulants yields higher glucose concentrations than NaF.

## Abstract

Summary: Blood samples were collected from 20 cows into 3 tubes with different anticoagulants, including sodium fluoride (NaF), dipotassium ethylenediaminotetraacetate (K2-EDTA), and lithium heparin (Li-Hep) tubes. Two different enzymatic reactions, peroxidase and glucose oxidase (PGO) and hexokinase (HK), were used for quantification of glucose concentration in the plasma samples collected with the different anticoagulants. Across both methods, samples collected in NaF yielded lower glucose concentrations compared with K2-EDTA and Li-Hep. Additionally, the samples quantified with HK yielded lower glucose concentrations than the same samples quantified with PGO.

Summary: Blood samples were collected from 20 cows into 3 tubes with different anticoagulants, including sodium fluoride (NaF), dipotassium ethylenediaminotetraacetate (K2-EDTA), and lithium heparin (Li-Hep) tubes. Two different enzymatic reactions, peroxidase and glucose oxidase (PGO) and hexokinase (HK), were used for quantification of glucose concentration in the plasma samples collected with the different anticoagulants. Across both methods, samples collected in NaF yielded lower glucose concentrations compared with K2-EDTA and Li-Hep. Additionally, the samples quantified with HK yielded lower glucose concentrations than the same samples quantified with PGO.

•Sodium fluoride yielded lower glucose concentrations compared with Li-Hep.•Sodium fluoride yielded lower glucose concentrations compared with K2-EDTA.•Enzymatic methods used for glucose measurement yielded different concentrations.

Sodium fluoride yielded lower glucose concentrations compared with Li-Hep.

Sodium fluoride yielded lower glucose concentrations compared with K2-EDTA.

Enzymatic methods used for glucose measurement yielded different concentrations.

Sodium fluoride (NaF), K2-EDTA, and lithium heparin are common anticoagulants used during collection of bovine blood for glucose concentration. Whereas NaF is considered the best anticoagulant for preservation of glucose, other anticoagulants are used because of their ability to simultaneously preserve other metabolites frequently measured in dairy science experiments. To simplify sample collection and reduce the need for multiple tubes, it may be possible to use tubes with anticoagulants other than NaF, provided they yield comparable glucose concentrations. Additionally, blood glucose concentrations are commonly analyzed using a peroxidase and glucose oxidase (PGO) colorimetric assay with a standard plate reader, but the use of a semi-automated chemistry analyzer with a hexokinase (HK) enzymatic reaction method is becoming more common in dairy research because it is also available and easy to use. Thus, the objective of this study was to determine the influence of the use of NaF, dipotassium EDTA (K2-EDTA), or lithium heparin (Li-Hep) as anticoagulants on glucose quantification, using both the PGO and HK enzymatic reaction methods. Blood samples from 20 fresh cows (7 ± 3 DIM) were collected into NaF, K2-EDTA, or Li-Hep plasma tubes on a commercial dairy farm (n = 60 samples). All samples were analyzed using both the PGO method, performed on a 96-well plate with a colorimetric microplate reader, and the HK method, conducted on a semi-automated chemistry analyzer. It was observed that in both methods, samples collected into NaF tubes had less glucose quantified compared with samples collected into K2-EDTA and Li-Hep tubes. Additionally, it was observed that in samples quantified with the HK method, the glucose concentrations were lower than when those samples were quantified with the PGO method. Thus, the K2-EDTA and Li-Hep anticoagulant could be used for glucose quantification to avoid cumbersome collection of several tubes, but results must be reviewed with caution as concentrations would be higher compared with those quantified with NaF. This observation is also conserved when quantifying glucose using the PGO and HK methods.