Justine, a good pharmacist is a blessing! I agree with Phyllis.
Sometimes if you take your tester with you for your lab appointment, you can take your blood with it, then have your lab done. That way, you can sort of calibrate it.
Also, many testers have solutions that you can use instead of blood, to check your strips and meter.
Another clue as to which meter is correct might be which one correlates most closely with your A1C numbers.
Hope this helps!