I'm 8 months post surgery and I'm going to see my surgeon for my 6 month follow up on Tuesday. I'm past due because my husband had a stroke which left me with little time to follow up. Everything has been going well, but I went to the lab at the hospital yesterday for post operative blood work. I have never been a difficult stick, but they seemed to have difficulty finding a vein. When they did find one, the blood was thick and dark and hemolyzed before they could fill the vial rendering the sample useless. They called a supervisor who brought an ultra-sound machine in to find a vein. They indicated that my veins were very small and continued to look. They found a usable one in my right arm. Supervisor stuck me and...nothing. Thick, dark blood that barely came out.

After securing my sample, she advised that it would be easier the next time if I drank plenty of fluids before I came in. I explained to her that I am a bariatric surgery patient and that I drink at minimum 64oz per day and that I have recently been trying to increase it and have been successful at getting in 80oz, every day this week. She then suggested that I eat more vegetables.

I see the Dr on Tuesday, so I will discuss this with him, but I can't help being paranoid about the thickness of my blood. My resting heart rate is 55-57, I have normal blood pressure. I'm at 1000 cal per day with 60-70g protein.

Anybody with a similar experience that maybe able to shed some insight?

When I draw blood from animals, usually their blood is that dark and thick when they are dehydrated. Like they said to you. I would recommend trying to drink more. And you can't tell if blood is hemolyzed until you spin it down. Unless it took so much force to pull you just know it's going to be hemolyzed.
As for the vegetable thing, no clue about that.

@Jess55I appreciate that, but I can't understand any way in the universe that I could be dehydrated. I am the most compliant with all requirements. Can you be dehydrated while getting the recommended or more than the recommended amount of fluid?

Depends on the temperature, your activity (and sweat) level. Keep pushing water. That is the key. 64 is not really a lot of water. Go for 80-100.