What does fpg reading of 131 blood glucose level mean ? i was not fasting yhough, when blood samples were taken

Nothing specifically: It depends on when you ate last. If it were fasting it might be significant. If you are worried about diabetes or hypoglycemia, ask your doctor for a specific test.

Fasting plasma gluco: Fpg or fasting plasma glucose is a measure of the glucose in your blood after 12 hours fasting, meaning nothing to eat or drink except water - for 12 hours. The test is not interpretable if your were not fasting. Do it again, fasting.