Determining Costs of the Diagnostic Protocol Determining the direct cost of the diagnostic protocol is relatively easy. The actual ratio of disease cost to diagnostic cost where no intervention should be made, or the intervention scaled back, will differ from producer to producer. As stated above, an intervention may be used both to prevent the condition and make a diagnosis. In reality, we do this more often than we actually perform laboratory tests. An example would include treating newborn pigs with penicillin by prescription, rather than investigating the etiologic cause of umbilical infection.
Diagnosis is determined by the response to the treatment.
If the results of the diagnostic investigation indicate no intervention is needed, the net benefit is a function of the cost of diagnostics and the cost of not initiating an unneeded intervention. If the result of the diagnostic investigation indicates that a different intervention is needed than would have otherwise been used if diagnostics had not been done, then the net benefit is a function of the cost of the diagnostic, the continued cost of the problem, the cost of the incorrect intervention, and the cost of the correct intervention. If the cost of intervention for a period sufficient to make a diagnosis is less than the cost of diagnostics, it would make economic sense to apply the intervention as the diagnostic tool. Higher cost ratios will require situation specific decisions. The challenge is to guess right without a diagnostic investigation and the choose the right intervention.