Most clinicians will be comfortable with the formulary concept when applied to outside laboratories. At first there might be resistance but most clinicians will quickly appreciate that there is a specific document which they can refer to, that shows the laboratory tests offered, the prices (if you choose to add this information), and what consults are needed. For example, a genetic test may require a genetics consult and order. In the absence of a formulary, clinicians often have to assume the burden of finding a laboratory that does the testing they want. Although more restrictive, the formulary eliminates this burden for them.
Instituting a laboratory formulary is a good way to get send-out testing under control. If send-out tests are only sent to labs that have your best, negotiated price, and certain tests are only done once per lifetime, then the formulary model should save the lab significant money in send-out testing. It will also make the process easier for the laboratory staff who can refer to the formulary when an esoteric test is ordered. Staff can quickly determine where to send the test, whether the test can be performed as ordered, or whether the clinician needs to modify the order.