What makes disease diagnosis difficult?
The following issues can make it difficult to test samples and/or to interpret test results:
Turbulent collection, rapid temperature changes, moisture, and rough handling increase haemolysis.
Remove the needle before expressing blood from a syringe into a tube as increased pressure causes haemolysis. Let samples cool to room temperature before refrigeration. Leave plain tubes to clot. To mix anticoagulant tubes, gently tilt from end to end.
Incorrect ratios of anticoagulant to blood may affect results. Insufficient volume will also limit the number of tests available.
Fill blood tubes to the indicated line to ensure correct anticoagulant concentration and to provide sufficient blood for multiple tests.
Too few samples
Take samples from cohort animals to allow thorough investigation of herd disease status. Ten blood samples are ideal. Supplying multiple samples reduces the risk of misinterpretation due to individual or diurnal variation.
Some blood parameters can break down quickly following collection. Depending on the tests required, collection and receival at the laboratory can be critical for getting an accurate result.
For haematology and thiamine tests, samples should be received by DDLS within 24 hours of collection. Samples taken for biochemistry tests should be received by DDLS within 48 hours of collection and kept cool (not frozen). Samples collected for virus testing can be received after 48 hours as once clotted, antibodies in serum remain stable for a prolonged period.
Blood sampling after veterinary treatment can significantly alter results.
Consider collecting blood before treatment and storing samples pending response to treatment. List any prior treatments on DDLS submission form.
Contact DDLS on +61 (0)8 9368 3351 or see the livestock biosecurity program contacts webpage.