A rapid field test for the measurement of bovine serum immunoglobulin G using attenuated total reflectance infrared spectroscopy.
BACKGROUND
Following the recent development of a new approach to quantitative analysis of IgG concentrations in bovine serum using transmission infrared spectroscopy, the potential to measure IgG levels using technology and a device better designed for field use was investigated. A method using attenuated total reflectance infrared (ATR) spectroscopy in combination with partial least squares (PLS) regression was developed to measure bovine serum IgG concentrations. ATR spectroscopy has a distinct ease-of-use advantage that may open the door to routine point-of-care testing. Serum samples were collected from calves and adult cows, tested by a reference RID method, and ATR spectra acquired. The spectra were linked to the RID-IgG concentrations and then randomly split into two sets: calibration and prediction. The calibration set was used to build a calibration model, while the prediction set was used to assess the predictive performance and accuracy of the final model. The procedure was repeated for various spectral data preprocessing approaches.


RESULTS
For the prediction set, the Pearson's and concordance correlation coefficients between the IgG measured by RID and predicted by ATR spectroscopy were both 0.93. The Bland Altman plot revealed no obvious systematic bias between the two methods. ATR spectroscopy showed a sensitivity for detection of failure of transfer of passive immunity (FTPI) of 88 %, specificity of 100 % and accuracy of 94 % (with IgG <1000 mg/dL as the FTPI cut-off value).


CONCLUSIONS
ATR spectroscopy in combination with multivariate data analysis shows potential as an alternative approach for rapid quantification of IgG concentrations in bovine serum and the diagnosis of FTPI in calves.
Department of Health Management, Atlantic Veterinary College, University of Prince Edward Island, 550 University Avenue, Charlottetown, PEI C1A 4P3, Canada. ielsohaby@upei.ca.|Infectious Diseases, Department of Animal Medicine, Faculty of Veterinary Medicine, Zagazig University, Zagazig, 44511, Sharkia Province, Egypt. ielsohaby@upei.ca.
Ibrahim
I
Elsohaby
Department of Health Management, Atlantic Veterinary College, University of Prince Edward Island, 550 University Avenue, Charlottetown, PEI C1A 4P3, Canada. shou@upei.ca.
Siyuan
S
Hou
Department of Health Management, Atlantic Veterinary College, University of Prince Edward Island, 550 University Avenue, Charlottetown, PEI C1A 4P3, Canada. jmcclure@upei.ca.
J Trenton
JT
McClure
Department of Health Management, Atlantic Veterinary College, University of Prince Edward Island, 550 University Avenue, Charlottetown, PEI C1A 4P3, Canada. C.B.Riley@massey.ac.nz.|Institute of Veterinary, Animal and Biomedical Sciences, Massey University, Palmerston North, 4442, New Zealand. C.B.Riley@massey.ac.nz.
Christopher B
CB
Riley
National Research Council of Canada, Medical Devices Portfolio, Winnipeg, MB, R3B 1Y6, Canada. Anthony.Shaw@nrc-cnrc.gc.ca.
R Anthony
RA
Shaw
Department of Health Management, Atlantic Veterinary College, University of Prince Edward Island, 550 University Avenue, Charlottetown, PEI C1A 4P3, Canada. Gkeefe@upei.ca.
Gregory P
GP
Keefe
D000818:Animals; D002417:Cattle; D005188:False Negative Reactions; D005189:False Positive Reactions; D005260:Female; D007112:Immunity, Maternally-Acquired; D007074:Immunoglobulin G / Q000097:blood*; D015999:Multivariate Analysis; D013055:Spectrophotometry, Infrared / Q000379:methods / Q000662:veterinary*
D007074:Immunoglobulin G