My child had bad stomach flu and her glucose blood level was 135. Can being sick make it high? Is. 135 a concern after not eating and throwing up?

Normal body response. When you are sick, your body secretes certain hormones in response to the stress on the body, including steroids. This will cause a rise in the blood glucose, even if the child hasn't been eating. It is totally normal and expected. She is not diabetic and nothing to worry about.