An increase in MCV due to alcoholism can slightly increase the HCT from
what I've seen at work, but it's purely mathematical. Larger RBC's take
up more space and will elevate the HCT out of proportion to HGB levels.

It also tends to lower PLT counts but I'm not sure why. Probably due to
an overall decrease in hematopoiesis which can occur with advanced liver
destruction. Platelets are also consumed rapidly during severe bleeding
episodes.

But, most chronic alcoholics that end up in the hospital usually have
low HGB/HCT levels due to gastrointestinal bleeding, especially
esophageal varices. Many terminal alcoholics that don't die of hepatic
failure die from organ failure due to excessive blood loss from GI
bleeding.

Even rapid blood product replacement cannot always correct organ failure
due to sudden drops in blood pressure.

Overall RBC total counts do not seem to be affected much initially until
advanced liver damage has occurred. I've seen many an alcoholic person
with elevated liver enzymes (and high blood alcohol levels) that have
perfectly normal RBC and HCT values with only slightly elevated MCV's
that were not in for bleeding episodes. They were there for other
reasons unrelated to their alcohol abuse.

It can be an indicator, but is not always present.