Minimum test volume to implement POCT

That really depends on the test, though.  Is patient care/satisfaction or revenue significantly affected by 5 tests?  Is it easy for you to oversee?
Our outpatient cath lab only performs about 5 hCG tests per month, but sending the test to the lab across the street leaves them waiting for about 45-60 minutes, which causes delays in their cases.  
We have a pediatric clinic that flies in an endocrinologist once a month, patients drive up to 4 hours to see them and they only run less than 10 A1c tests on their device per month.  Definitely a significant time and patient satisfaction impact.
Both of those got a Yes from our POC committee.
Our Pediatric oncology/infusion department wanted to add a POC CBC analyzer for their oncology patients.  They estimated 5-10 tests per month.  It was going to be really expensive, many of the CBCs would have to be sent to lab anyway for confirmation, and it would only save 10-15 minutes.
That one got a No. 

I've tried to create a minimum test volume requirement for new POCT requests in our physician offices and have been unsuccessful due to each request being unique, each clinic having different patient populations etc. We have a POCT application that requestors must fill out. After submission we have a small committee consisting of our POC Medical Director, Quality Medical Director, POC manager, and POCCs. When needed we loop in other specialties to assist with a new POC test request review. Our POC Medical Director also weighs the amount of oversight required from the POCCs and if its worth our time to oversee 5 tests. 

Kari, would you be willing to share your POCT application form? 

It depends on the test based on cost and complexity.  I am in a hospital, not a doctors office, but for something waived that is relatively low cost, we usually say you must report at least 1 a month.  I feel like this should be higher, such as your number of 5/month.   I posted our form we use on the POCT Needs Assessment form question you asked!

I had a moderate complexity test that was very low volume that providers said we want just in case. It took about 10 years and many leadership changes before I got heard that it was not worth it. QC, Proficiency testing and linearity, not to mention the cost for maintaining competency documentation. We spent $7K/ year with a volume of 10/year (cost per test cost = $700 at a reimbursement rate of about $40/test). I was so glad that finally a person that understands cost and effectiveness bless to have that test discontinued. You have to present the cost, options if not done at POCT and its effectiveness (patient care and result quality compared to being done using a large instrument).