This calculator is for general information and education. It is not medical advice and does not replace the judgment of a doctor, nurse or pharmacist who knows the full clinical picture.
A nutrition score for older adults
The Geriatric Nutritional Risk Index (GNRI) was designed in 2005 by Olivier Bouillanne and colleagues to predict the risk of nutrition-related complications and death in hospitalized older adults. It combines one biological marker, serum albumin, with the gap between a person’s weight and their ideal weight.
The formula
GNRI = 1.489 × albumin (g/L) + 41.7 × (current weight ÷ ideal weight)
The weight ratio is capped at 1: a weight above the ideal weight counts as 1. The ideal weight comes from the Lorentz formula:
- men: height (cm) − 100 − (height − 150) ÷ 4
- women: height (cm) − 100 − (height − 150) ÷ 2.5
US laboratories report albumin in g/dL; the calculator multiplies by 10 to get g/L.
Example
A man 5 ft 9 in tall (175 cm) weighing 150 lb (68 kg) has an ideal weight of about 152 lb (69 kg). With albumin at 3.5 g/dL (35 g/L): GNRI = 1.489 × 35 + 41.7 × 0.99 = 93.3, a low risk.
| GNRI | Nutrition-related risk |
|---|---|
| above 98 | None |
| 92 to 98 | Low |
| 82 to 91 | Moderate |
| under 82 | Major |
When it is useful
The GNRI works when a person cannot answer a questionnaire, for example in confusion or dementia, because it uses only weight, height and a blood test. It is widely studied in dialysis, heart failure and cancer patients, where a low GNRI predicts complications and mortality.
Limits
- Albumin falls during inflammation, infection, liver disease and kidney losses, independently of nutrition, so a low GNRI can reflect illness as much as undernutrition.
- Edema and dehydration distort the weight.
- It does not include recent weight loss or food intake, which questionnaires such as the MNA capture.
Use the GNRI as a screening tool alongside a clinical nutrition assessment.