Congratulations to you for wanting to take the next step!
You're describing care management services. I recently started a business providing these types of services. You can start a business fairly easily by following your state's guidelines. The beauty of a nurse starting a business is that it's fairly inexpensive (start-up costs will probably be between $1,300-4,000 depending on how wisely you spend and how much you want to spend to get started).
I would start by coming up with a business plan, then decide on your business name (you can go to your state's website to look up the availability of names you're interested in), then apply for a business (I recommend LLC) in your state. ...and don't forget your insurance (I recommend the Nurse Service Organization).
After that, you'll get your marketing and advertising materials (i.e. car magnets, business cards, refrigerator magnets, brochures, letter head, etc - I recommend www.vistaprint.com
for this), set up a website & Google AdWords to help get your name out there, and develop your own way of charting and record keeping.
I did a lot of research to get my business started (hundreds of hours - I didn't track, but it was a lot
of time). Start by doing online research specific to the rules and regulations in your area - Google will be your best friend!
I also recommend checking out www.nnba.net
(National Nurses in Business Association - Pat Bemis is the president - I've read 2 of her books & found them very helpful).
I have a side note regarding the hands-on care (blood draws) you mentioned - this will lead to additional costs for your liability insurance. You might consider offering transportation services instead, or set-up home draws through the client's doctor's office or a local home health agency. ...just a thought.
I hope this information is helpful. Good luck to you!!