Your initial question was very broad so I could not know our exact intention.
An HDL below 40 in a man is thought to be a negative cardiac risk factor and counts against you when determining risk for future cardiac events. I cannot tell you how exactly how much an HDL of 38 contributes to your risk however.
The A1C of 6.2% is out of the normal range and may mean that you have diabetes. You need to be formally tested by your doctor. Current recommendations are for a fasting glucose or a 2 hour glucose tolerance test to be performed for the actual diagnosis of diabetes.
I know what HDL means. I am 64 and my HDL is below 40. It is 38. What does a measure of 38 mean for a 64 year old man? JoJofromTucson
2nd question is: My hemoglobin A1c is 6.2 %. What does this measurement mean? According to my blood report I am slightly out of the preferred range. JoJofromTucson
I think the HDLC is your HDL cholesterol(high density lipoprotein cholesterol). This is the "good cholesterol" in your body. Depending on your gender, there are optimal levels. For women optimal levels are often above 50, and for men above 40.