The glutaraldehyde test and its use in dairy cattle

Abstract

During a physical examination of cattle, it is often difficult to evaluate inflammatory processes, particularly in cases where the inflammation occurs in deeper regions. The glutaraldehyde test (GT), carried out using a sample of whole blood, allows the visual and semiquantitative identification of an inflammatory process in cattle. Considering that there are few biochemical tests that can be used in the field, the objective of this study was to verify the efficacy of the GT in detecting and predicting mild and severe inflammatory processes in bovine species, classified according to a physical examination, and in the presence of different diseases or lesions. The GT was used in conjunction with a physical examination in 176 cows over 12 months of age, with additional laboratory evaluations of packed cell volume, total protein, albumin, globulin, and fibrinogen. Using a cutoff point at 3 minutes of coagulation, the GT showed a sensitivity of 35.1%, specificity of 94.1%, positive predictive value of 74.1%, and negative predictive value of 75.2%. The GT correctly detected the most severe inflammatory processes under the field conditions of this study. The GT is a diagnostic aid that can be used as a fast and simple screening test during the physical examination of cattle.

Association of results of the glutaraldehyde coagulation test with plasma acute phase protein concentrations and hematologic findings in hospitalized cows

“…Central findings of this study indicate that there is considerable diagnostic agreement between positive GAT results and increased plasma concentrations of haptoglobin and SAA, therefore confirming findings of previous studies that the GAT represents a clinically useful screening test for cow-side detection of inflammatory disease conditions ( 4–7 ). Results of the performed regression analyses indicate that shortened GAT coagulation times were most closely associated with higher than normal plasma globulin concentrations and a lower than normal plasma or serum albumin to globulin ratio, which is also in line to findings of previous studies in cattle ( 3 , 4 , 6 , 7 , 34 ) and horses ( 38 ). Use of the obtained power regression function for plasma globulin concentration ( Equation 2 ) indicates that a coagulation time of 6 min predicts an abnormal plasma globulin concentration of ≥52 g/L ( Figure 1 ), which is similar to a reported cut-off value of 7 min in a previous study to predict a higher than normal total sum of gamma-globulin and fibrinogen concentrations ( 4 ).…”

“…Cows were grouped according to the GAT coagulation time defined as markedly shortened (≤3 min), moderately shortened (4 to ≤8 min), slightly shortened (9 to ≤15 min), and normal (>15 min). In a previous study ( 7 ), coagulation times ≤3 min, >3 to ≤6 min, >6 to ≤15 min, and >15 min were empirically interpreted as indicator of a severe, moderate, mild, and non-detectable inflammatory response. In the present study, a coagulation time of 8 min was however used for differentiation between moderately and slightly shortened test results, because it was identified as a clinically useful cut-off value to detect a higher than normal gammaglobulin and/or fibrinogen concentration ( 4 ).…”

“…In adult cattle, a coagulation time of the whole-blood GAT of >15 min (based on use of a 1.25% glutaric aldehyde solution in a ratio of 1:1) is generally considered as a negative test result ( 3 , 4 , 6 , 7 ), whereas a coagulation time of 7 and 8 min were identified as clinically useful cut-off values to predict an elevation of the total sum of fibrinogen and gamma globulin concentrations of >32 g/L (proportion of correct classifications 82%) ( 4 ). Highly shortened coagulation times (≤3 min) are usually associated with serious conditions (mainly chronic bacterial infections or purulent conditions) such as pneumonia, reticuloperitonitis, endo- or pericarditis, pyelonephritis, arthritis, or deep digital sepsis ( 5 , 6 , 10–13 ).…”