Blood Sugar Essentials

How much insulin it takes to hold your blood sugar steady, next to your three-month average and the blood fats that shift when that gets harder.

Glucose is the last thing to go wrong. For years before a fasting glucose creeps up, the pancreas keeps it in range by producing more insulin, and that rising insulin is the problem itself. It drives fat storage around the organs, raises blood pressure and triglycerides, and pushes testosterone down in men and up in women. Fasting insulin catches that stage. A1c gives your average blood sugar over roughly the past three months, which is the number that defines prediabetes and diabetes and the one a doctor will act on. The lipid panel earns its place because the triglyceride-to-HDL ratio tracks insulin resistance closely enough that many clinicians read it as a second insulin test, and because the same process that raises insulin raises triglycerides first. Fast for nine to twelve hours before the draw. Water is fine.

Blood is drawn at a Quest Diagnostics, Labcorp or BioReference patient service center. Price by laboratory: Quest Diagnostics $19, Labcorp $37 or BioReference $45. Your price depends on your state and the laboratories near you. Enter your ZIP code to see them.

What’s included

• Hemoglobin A1c: The percentage of hemoglobin with glucose attached, which reflects average blood sugar over about the past three months.
• Insulin: Insulin, the hormone that signals cells to take up glucose from the blood.
• Lipid panel: Total cholesterol, HDL cholesterol and triglycerides, with calculated LDL cholesterol, non-HDL cholesterol and the cholesterol-to-HDL ratio.
• Glucose: Glucose, the main sugar in the blood and the body's main source of energy.

Tests you can add

• C-reactive protein, high-sensitivity (hs-CRP): C-reactive protein, a protein the liver releases during inflammation, measured with a high-sensitivity method.
• Apolipoprotein B (ApoB): Apolipoprotein B, the main protein on LDL and other cholesterol-carrying particles.
• Uric acid: Uric acid, a waste product of purine breakdown that the kidneys clear.
• Vitamin D (25-hydroxy): 25-hydroxyvitamin D, the main form of vitamin D circulating in the blood.

Before your draw

Fasting required.

Fast for 9 to 12 hours before your draw; water is fine. The insulin test needs a fasting sample. If you take insulin or other diabetes medicine, ask your clinician how to take it while you fast. Don't stop your usual medicines unless your clinician tells you to. If you take biotin (vitamin B7), including in hair, skin and nail supplements or multivitamins, have your blood drawn at least 8 hours after a usual dose, or at least 72 hours after a high dose. If biotin was prescribed, ask your clinician before stopping it.