MUST Score — The NHS Malnutrition Screening Tool Explained

What Is the MUST Score?

The **Malnutrition Universal Screening Tool (MUST)** is a 5-step screening tool developed by the British Association for Parenteral and Enteral Nutrition (BAPEN) and recommended by NICE for use across the NHS. It identifies adults at risk of malnutrition or obesity-related undernutrition based on three simple inputs: BMI, recent weight loss, and the effect of acute illness on food intake.

MUST is used routinely in NHS hospitals, care homes, GP surgeries, and community settings. If you've been admitted to hospital, a nurse has almost certainly screened you using MUST within 24 hours of arrival.

When Is MUST Used?

The NICE guideline CG32 recommends MUST screening for all adults:

MUST is **not** designed for use in pregnancy, in children, or in adults with severe fluid disturbance (such as ascites or oedema) where weight measurements may be unreliable.

How the MUST Score Is Calculated

MUST uses three components, each scored from 0 to 2. The total score is the sum and decides the risk band.

Step 1: BMI score

| BMI | Score |

|---|---|

| 20.0 or above | 0 |

| 18.5 – 19.9 | 1 |

| Below 18.5 | 2 |

If accurate height and weight aren't available, you can use an alternative measurement (such as ulna length and mid upper-arm circumference). The full alternative-measurement guidance is in the BAPEN MUST guide.

Step 2: Weight-loss score

Unintentional weight loss in the past 3 to 6 months:

| Weight loss | Score |

|---|---|

| Less than 5% | 0 |

| 5 – 10% | 1 |

| More than 10% | 2 |

Step 3: Acute disease effect score

If the person is acutely ill **and** there has been or is likely to be no nutritional intake for more than 5 days: score **2**. Otherwise score **0**. This step rarely applies outside hospital.

Step 4: Add the three scores

Add the BMI score, weight-loss score, and acute-disease score together.

Step 5: Use the total to determine the risk band

| MUST total | Risk | Action |

|---|---|---|

| **0** | Low | Routine clinical care. Repeat screening regularly. |

| **1** | Medium | Observe. Document 3-day dietary intake. If improved, repeat screen. |

| **2 or more** | High | Treat. Refer to dietitian or nutrition support team. |

Try It Yourself

We've built a free [MUST score calculator](/) that calculates BMI from your height and weight, asks for recent weight loss, asks about acute disease, and returns your MUST risk band with NICE-recommended next steps.

A Worked Example

Mary is 78, weighs 48 kg, is 1.62 m tall, has lost 4 kg in the past 4 months, and is currently recovering from a chest infection that left her too tired to cook for over a week.

Mary is at **high risk** and should be referred to a dietitian.

Why MUST Matters

Around **1 in 3 hospital admissions** in the UK involve someone at medium or high risk of malnutrition. Unaddressed malnutrition increases hospital length of stay, post-operative complications, infection risk, and mortality. Treating it costs the NHS less than ignoring it.

For older adults in particular, even a 5% unintentional weight loss meaningfully raises the risk of falls, fractures, and hospital admission. Screening with MUST catches this early.

How to Improve Your MUST Score

If you score 1 or above, the priority is to increase nutritional intake without making meals stressful.

For people with high BMI but rapid unintentional weight loss, MUST still flags risk. Don't assume someone overweight cannot be malnourished — sarcopenic obesity (low muscle, high fat) is common in older adults.

The Bottom Line

MUST is a simple, validated, NHS-standard malnutrition screen that anyone can perform with a tape measure and a set of scales. A score of 0 is reassuring; 1 needs observation; 2+ needs treatment. If you or a relative scores 2 or more, see your GP for a dietitian referral.

For BMI-based screening, start with our free [BMI calculator](/). For child malnutrition screening, use age-and-sex percentile bands instead — see our [child BMI calculator](/child-bmi-calculator).