blood sugar
Medical/biological term for glucose in the blood.
When the concentration of blood sugar is high, the risk of diabetes increases.
More common and concise term for 'blood sugar', used in compounds like 血糖値 (blood sugar level). 血液中の糖 is a longer, more explicit phrase.
Compound of 血液 (blood) + 中 (in) + の (possessive particle) + 糖 (sugar). Literally 'sugar in the blood'.