How to screen, diagnose and code malnutrition

The clinical work usually gets done. The step that gets dropped is the last one, and it is the one that makes the work visible in the hospital’s activity data.

1. Screen — MST

Two questions: has appetite decreased, and has there been unintentional weight loss. A score of 2 or more is “at risk” and triggers assessment.

Watch the “unsure” answer on weight loss — it scores 2, not 0. A patient who does not know is treated as meaningful risk, because slow substantial loss is exactly what people fail to notice.

2. Assess

Anthropometrics, intake history, clinical context. This is the clinician’s work and no part of it is automated.

3. Diagnose — GLIM, and it is two steps

GLIM is not a screening tool. It requires:

• Step 1: a validated screen already positive
• Step 2: at least one phenotypic criterion (weight loss, low BMI, reduced muscle mass) and at least one aetiological criterion (reduced intake or assimilation, or disease burden/inflammation)

Severity is staged on the phenotypic criteria only.

The step most often skipped is the first. GLIM applied without a positive screen is not GLIM.

4. Code it

A completed GLIM diagnosis supports ICD-10-AM coding. In AI Dietitians the GLIM calculator composes with a coding helper, so the diagnosis and the suggested code come out of the same assessment rather than being reconstructed by a coder from your prose a fortnight later.

This is the step that pays for the other three. Coding is what carries dietetic work into the activity data that drives hospital funding. A ward that screens diligently, assesses thoroughly and writes “malnutrition present” in the notes has done all the clinical work and captured none of the value.

5. Check the working

Every calculator shows its line-by-line arithmetic — which criteria were met, which were not, and how the severity was staged. Keep it: it is what makes the diagnosis defensible when someone asks six weeks later.

References

• Ferguson M, Capra S, Bauer J, Banks M (1999). Development of a valid and reliable malnutrition screening tool for adult acute hospital patients. Nutrition 15(6):458-464.
• Cederholm T, Jensen GL, Correia MITD, et al. (2019). GLIM criteria for the diagnosis of malnutrition — a consensus report from the global clinical nutrition community. Clinical Nutrition 38(1):1-9.
• Independent Health and Aged Care Pricing Authority, Australian Coding Standards / ICD-10-AM
• Dietitians Australia, Professional Practice Standards

---

Screening tools identify risk and are not diagnostic. Coding decisions are made under your health service’s coding standards. This article is educational information for clinicians.