Comparison of the In-House analyser with Greendale
Introduction
The use of in-house machines is very important for veterinary clinicians to offer a quick response for extremely unwell animals; however, they do have limitations. A study was carried out to determine how well the in-house biochemistry machines correlated to the results produced by our large industrial biochemistry analysers.
Method and Results
Seven samples were selected from first opinion clinics. These were initially tested on the in-house machines and then sent to Greendale for testing. Below is a table summarising the results.
The mean difference represents the average difference in the results for the in-house machine when comparing Greendale’s results. The column with ‘SD’ represents the standard deviation of the data, in other words, what is the degree of variability between the two results.
| Analyte | N | Mean Difference | SD |
| Albumin | 7 | 1.9 | 1.35 |
| ALP | 7 | 71.0 | 78.73 |
| ALT | 7 | 19.3 | 12.61 |
| Amylase | 7 | 167.6 | 446.16 |
| Urea | 7 | 0.5 | 0.90 |
| Calcium | 7 | -0.2 | 0.14 |
| Cholesterol | 7 | 0.2 | 0.24 |
| Creatinine | 7 | 4.6 | 18.95 |
| Glucose | 7 | -0.5 | 0.91 |
| Phosphate | 7 | 0.0 | 0.08 |
| Tbilirubin | 7 | -1.91 | 3.53 |
| Total Protein | 7 | -5.9 | 3.34 |
| Na | 3 | -5.3 | 0.58 |
| K | 3 | -0.1 | 0.17 |
| Cl | 3 | -4.0 | 0.00 |
Summary of Findings
From the data, one could see that the results match very well between the in-house analyser and Greendale. This therefore demonstrates that, for emergency work, the general quality is quite good for the in-house machines. However, there was a large degree of variability demonstrated with ALP, ALT, Amylase and Creatinine. In cases were the levels might be bordering on the upper or lower limits of the reference range, this could have a huge impact on interpretation, as the sample would give false low or high results.
Unlike the in-house machines, in the laboratory, we calibrate and run quality control materials (samples spiked with known analyte values) regularly during the working day. This is carried out to ensure that there is no variability, thus giving us a high degree of confidence that the results produced in our laboratory is the same at any time of the day, month or year. We also receive and test samples from external quality assurance reference laboratories twice a month. The purpose of this is to make sure that our results also agree with other laboratories in the UK.
Conclusion
Although you can have a degree of confidence in the results that are produced by the in-house machines, there will be variability and therefore errors in interpretation of certain analytes from time to time. We only took seven samples; a larger sample number would probably have demonstrated an even greater degree of variability, not just when comparing Greendale, but also when comparing the results from one clinic to another.
The in-house machines are therefore designed for getting results for animals that require results extremely quickly, i.e. collapsed dog, and not for general diagnostics use. In most cases there is not such an urgency to obtain pathology results, and the quality of service you get from Greendale would far out way the advantages of having such a quick response.
From the feedback I get from practices that use in-house machines in a limited fashion, the vets tell me that it is just a mater of educating your clients to realise that if accurate results and therefore interpretation is required, they will not be able to get instant interpretations. If a comparison is made with the human sector, were the pathology service is a lot more heavily regulated, a patient can wait anything up to four days for their results, a fact that they are used to, and therefore there is a lack of resistance.
So to summarise, if used appropriately, the combination of in-house machines and Greendale offer best of both worlds, were, for emergency treatment, the clinician can use in-house machines for a quick response and for general use and confirmation purposes one should use Greendale.