FYI: i couldn't give blood today because my diastolic reading was too low. they took it 3 times. the first time they said that the bottom number didn't stop going low, it went down to the low 20s, the next 2 times it was 40 and 44. they didn't tell me the top number. it's been going low for a while now, but never below 40. would my blood pressure be affected by having either diabetes or hypoglycemia? should i ask to be tested for them?