NRI Matrix • Prognostic Nutritional Index
Input the albumin and weight data to visualize the nutritional risk index and severity stratification.
Guidelines & Evidence
Verified
Last Review: 2026-07-17
When to Use
When to Use
Objective quantification of nutritional risk in hospitalized patients (especially surgical candidates)
To predict post-operative complications and hospital length of stay
To identify patients who may benefit from pre-operative parenteral or enteral nutrition
Biological Anchors
The NRI relies on two primary markers: Serum Albumin (a marker of visceral protein status and systemic inflammation) and the ratio of Current Weight to Usual Weight.
How it Works
The NRI Formula
NRI = (1.519 × Albumin [g/L]) + (41.7 × [Current Weight / Usual Weight])
Interpretation Thresholds
| > 100 | Not at risk |
| 97.5–100 | Mild Risk |
| 83.5–97.5 | Moderate Risk |
| < 83.5 | Severe Risk |
Weight Ratio Note
If the Current Weight is greater than the Usual Weight, the ratio is capped at 1.0.
Clinical Pearls
The Albumin Caveat
Albumin is an "Acute Phase Reactant." In the setting of severe sepsis or trauma, albumin levels drop due to systemic vascular leak and liver prioritization of inflammatory proteins (like CRP). Thus, a low NRI in an acutely ill patient may reflect "Inflammatory Distress" as much as "Nutritional Deficiency."
Predicting Surgical Failure
Patients with a "Severe Risk" NRI (< 83.5) have a significantly higher rate of anastomotic leaks and surgical site infections. Guidelines often recommend delaying elective major surgery for 7–14 days of intensive nutritional "re-stacking" in this group.
Clinical Pearls
NRI is more objective than the Subjective Global Assessment (SGA) but less comprehensive regarding functional status
Albumin half-life is ~20 days, so the NRI reflects chronic rather than hyperacute nutritional status
Weight measurements should ideally be "Dry Weight" to avoid false results from oedema or ascites
Next Steps
Management Pathways
01
Severe Risk (< 83.5): Clinical dietitian referral; consider home parenteral nutrition (HPN) or enteral tubes pre-surgery.
02
Moderate Risk: High-protein oral supplements; monitor weekly weight.
The Evidence
The Foundational System
Study protocol: a randomized clinical trial of total parenteral nutrition in malnourished surgical patients.
Buzby GP et al. • American Journal of Clinical Nutrition. 1988;47(2 Suppl):366-81. The original Veterans Affairs (VA) nutritional study.
View Source• . ;
Origins & History
The Veterans Affairs Study
Developed for the VA Total Parenteral Nutrition Cooperative Study. It proved, for the first time in a large RCT, that identifying and treating malnutrition before surgery could significantly reduce postoperative morbidity and mortality.
Last Comprehensive Review: 2026-07-17