My 3 year old had a glucose number of 67. Test said anything below 67 is hypoclycemic. Is that true?

In septmeber my 3 year old had his glucose numbers tested and they were 67. Test scale said anything under 67 was hypoglycemic. Earlier this month he was retested (after changing diet) and his levels are now 87. Must also say this was with fasting. Wondering if it was the diet that made the difference.....