Nutritional Assessment

Core Concepts

Screening comes first

Screening is a quick, standardized way to identify people at risk so they can get a deeper look. It is usually done on admission and repeated during a stay, using a few simple questions and measures — recent weight change, recent intake, illness or stress — to flag risk. A positive screen does not diagnose malnutrition; it triggers referral for a comprehensive assessment. Institutions select validated tools (for example, the Malnutrition Universal Screening Tool or the Mini Nutritional Assessment, depending on setting and population). Exact tools and referral thresholds vary by institution and guideline — verify against your facility's policy and current references.

The five data streams

A comprehensive assessment combines five types of information:

1. Dietary history. What the person actually eats: a 24-hour recall, food frequency questionnaire, food diary, or usual-pattern diet history. Recall depends on memory — people forget snacks and under-report portions — so treat it as a starting point, not a precise record.
2. Anthropometric measures. Height, weight, body mass index (BMI, a weight-for-height index), and sometimes arm circumference or skinfold thickness as estimates of muscle and fat stores. Weight measured consistently over time is the most useful single measure.
3. Biochemical data. Laboratory values that can support the picture, such as markers of protein status. Labs are influenced by inflammation, fluid shifts, and illness, so they are supporting evidence, never proof — always pair them with physical and dietary findings and current reference ranges. Specific markers and interpretation should be checked against current references before drawing conclusions.
4. Physical examination. Observation of skin, hair, nails, mucous membranes, and mouth for findings that can accompany deficiencies (for example, dry brittle hair, changes in the tongue or mouth, poor skin integrity). Most such signs are nonspecific — they raise questions rather than answer them.
5. Client history. Medical diagnoses, surgeries, gastrointestinal symptoms, medications that affect appetite or absorption, chewing and swallowing problems, dental health, and the ability to shop, cook, and feed oneself. Social and cultural context matters too: finances, food access, living situation, mental health, and religious or cultural food practices all shape what a person can and will eat.

Weight: the story told in numbers

Weight change is the most informative single trend in nutritional assessment. Weigh consistently — the same scale, similar clothing and time of day — and compare readings over time, because a single reading means little. Unintentional weight loss is a red flag: it can signal inadequate intake, impaired absorption, or the body burning its own stores. Two cautions: sudden weight changes are often fluid shifts (edema, diuresis, IV fluids), not tissue loss; and the percent-weight-loss thresholds used to grade severity vary by guideline — check current references rather than memorizing one cutoff.

From data to a picture — and who does what

Assessment is synthesis: compare intake with needs, current weight with baseline, and physical signs with history. Separate observations ("weight 4 kg lower than 3 months ago," "ate less than half of lunch") from interpretations ("at risk for malnutrition related to decreased intake"), and document objectively. Nurses screen, gather data, observe intake, weigh, document, and flag concerns — but comprehensive assessment, diagnosis of malnutrition, and prescription of therapeutic diets are typically the role of the registered dietitian nutritionist (RDN). Nurses implement diet orders, monitor tolerance, and educate the person and family. Exact role boundaries vary by state and institution; follow facility policies and scope-of-practice guidance.

Common Confusions