"I wonder if A1c tests can skew, where periodic high blood sugar levels eclipse relatively normal control over a span of time. imagine a rug which has been clean for a while, but a cup of wine recently dropped will make it appear stained. Is this parallel apt for A1c results?"
You're mixing fasting glucose or an OGTT test with an A1c. Fasting and/or an OGTT captures your glucose at the time of the test, not what is was 3 hours prior, the day or week before.
The A1c is used to measure your blood sugar control over several months. It can give a good estimate of how well you have managed your diabetes over the last 2 or 3 months. In general, the higher your A1c, the higher the risk that you will develop problems such as:
* Eye disease
* Heart disease
* Kidney disease
* Nerve damage
This is especially true if your A1c remains high for a long period of time. The closer your A1c is to normal, the less risk you have for these complications.
The A1c measures the glycosylated hemoglobin... simply stated, tells you how much of your red blood cells have glucose attached. Since red blood cells live 120 days, the test can tell how well your blood glucose has been controlled over 3 months. Normal level (without diabetes) is below 7%. A1c is now being recommended to diagnose Type II diabetes, instead of doing 2 FPGs. It's a very accurate test. Keeping your BG under control will bring it down. Good luck!