1. As noted in an earlier post, you can now make a reservation online for SQ lab work, including even at your nearby Safeway. The earliest online reservation slot is 7:30 a.m. But, the lab actually opens at 7:00 a.m. for walk-ins, and there likely will be 1 or 2 at the most and often none. So, if you're fasting, you can show up at 7:00 a.m., and if there's a wait do some shopping.
2. Being in the midst of the Jewish High Holy Days, if you need lab work for which fasting is required, scheduling that lab work for Yom Kippur morning might be seen as a win/win, and you'll still have no problem making it on time for the morning services at Shul.