Three numbers quietly control your glucose all day. Here's what each one does — in plain English, with no jargon.
Basal insulin is the slow, steady insulin that runs in the background, keeping your glucose stable between meals and overnight. On a pump it's set as a basal rate (units per hour); on injections it's long-acting insulin (like Lantus or Tresiba).
If your glucose drifts up or down when you haven't eaten for hours, that's usually a basal issue — either the rate is off, or it needs to change at different times of day.
ICR (insulin-to-carb ratio) is how many grams of carbohydrate one unit of insulin covers at mealtime.
A ratio of 1:10 means 1 unit of insulin for every 10 grams of carbs. A 1:15 is "weaker" (more carbs per unit); a 1:5 is "stronger" (fewer carbs per unit).
If you spike after meals but come back down, your ICR might be too weak (you need more insulin per carb). If you crash after meals, it might be too strong.
ISF (insulin sensitivity factor) — sometimes called the correction factor — is how much one unit of insulin lowers your glucose.
An ISF of 1:50 mg/dL (or 1:2.8 mmol/L) means one unit drops you by about 50 mg/dL. A lower ISF number means you're more insulin-resistant (one unit does less); a higher number means more sensitive.
Basal holds the line between meals, ICR handles the food, and ISF handles the corrections. When glucose is off, the first step is figuring out which of the three to look at — that's exactly the kind of thing a report can reveal, but only if you can read it.
Don't decode it alone. Upload your CGM/pump report and Piabetes points you at the settings worth reviewing — basal, ICR, or ISF.
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