This tool builds a correction-dose insulin sliding scale from first principles and converts a continuous IV insulin order into a pump rate. Rather than printing a one-size-fits-all table, it uses the patient’s own target glucose and insulin sensitivity so the doses are individualised.
How it works
Each row of the scale uses the correction formula:
Correction units = (current BG − target BG) ÷ ISF
The insulin sensitivity factor (ISF) is the number of mg/dL that one unit of
rapid-acting insulin is expected to lower the blood glucose. A widely used
bedside estimate for rapid-acting analogues is the 1800 rule: ISF ≈ 1800 ÷ total daily dose. So a patient on 60 units/day has an ISF of roughly 30. When
the current glucose is at or below target the formula gives zero or a negative
number, which the tool clamps to 0 units — you never give a negative
correction.
Converting the IV drip
For continuous IV insulin, the pump rate follows directly from the bag concentration:
Rate (mL/hr) = ordered units/hr ÷ concentration (units/mL)
The standard intensive-care mix of 100 units of regular insulin in 100 mL of
saline is 1 unit/mL, so an order of 4 units/hr simply runs at 4 mL/hr.
Understanding the insulin sensitivity factor in practice
The ISF is the most consequential input in the scale. An ISF that is too high (meaning you think insulin is more potent than it is) will suggest too-small correction doses and leave glucose elevated. An ISF that is too low will suggest too-large doses and risk hypoglycaemia. Two common bedside estimation rules:
- 1800 rule (rapid-acting analogues):
ISF = 1800 ÷ total daily dose (TDD) - 1500 rule (regular insulin):
ISF = 1500 ÷ TDD
For example, a patient whose TDD is 45 units of a rapid-acting analogue has an
estimated ISF of 1800 ÷ 45 = 40 mg/dL per unit. Enter that as 40, set a target
of 120 mg/dL, and the scale will show correction doses for each glucose band.
ISF estimates are starting points. Actual sensitivity varies with illness, steroids, infection, renal function, and time of day. The scale should be reviewed and adjusted based on the patient’s actual glucose response.
Worked example: reading a generated scale
Say the target is 120 mg/dL, ISF is 30 mg/dL per unit, and the table rows start at 150 mg/dL with 30 mg/dL band widths. The first few rows would read:
| Blood glucose band | Correction formula | Suggested dose |
|---|---|---|
| 150–179 mg/dL | (165 − 120) ÷ 30 | ~1.5 units |
| 180–209 mg/dL | (195 − 120) ÷ 30 | ~2.5 units |
| 210–239 mg/dL | (225 − 120) ÷ 30 | ~3.5 units |
Midpoint values are used for each band. Doses should be rounded to the nearest 0.5 or whole unit according to institutional protocol.
Notes and safety
A correction scale is a planning aid, not a complete regimen. Sliding scales used alone are discouraged in hospital because they chase hyperglycaemia after it happens; basal-bolus dosing controls glucose far better. Always follow your institution’s protocol, double-check doses with a pharmacist, and monitor for hypoglycaemia. All calculation runs locally in your browser. This tool is intended to support, not replace, clinical judgement.