Nutrition · Topic 11 of 12
Nutritional Screening & Assessment
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Nutritional Screening & Assessment
A nutrition screen quickly finds who is at risk of malnutrition; a positive screen triggers a full assessment. The danger is missing it — weight, BMI and labs can look falsely reassuring.
Check it in order
Screen first; a positive screen gets a full assessment
Screening or assessment?
A screen finds who is at risk; it does not diagnose
| Screening | Assessment | |
|---|---|---|
| What it does | Quick check that finds who is at risk — does not diagnose | Full nutrition assessment, by or with a registered dietitian |
| When | Within 24 hours of admission | After a positive screen |
| Uses | MST, NRS-2002, MUST, MNA short form | History and diet, physical exam, anthropometrics, labs |
Validated screening tools
The MST asks two questions: weight loss and eating less
Most validated screening tools do not use albumin or prealbumin; they rely on weight change, intake, BMI and disease severity.
Prealbumin or albumin?
Prealbumin changes within days; albumin lags for weeks
| Prealbumin | Albumin | |
|---|---|---|
| Normal | Normal prealbumin 15–36 mg/dL | Normal albumin 3.5–5.0 g/dL |
| Half-life | 2–3 days | About 20 days |
| Use | Trend serial levels to see early response to nutrition support | Lags for weeks — slow to show a change |
Red flags — don't wait for the score
Unintentional weight loss is the simplest red flag
Edema can keep scale weight stable while muscle is lost.
Common errors
No single number proves or rules out malnutrition
Muscle can be lost while body fat is preserved. Infection, inflammation, liver or kidney disease and fluid shifts lower albumin and prealbumin regardless of intake.
Monitor & teach
A balanced diet with a variety of foods comes first.
Screen within 24 hours — over 5% unintentional weight loss in a month is the red flag. No single lab or BMI proves or rules out malnutrition: prealbumin moves in days, albumin in weeks.
Sources · Key Nutrition Screening, Assessment, and Malnutrition Diagnostic Processes and Tools for Adults (ASPEN) · Malnutrition in Hospitalized Adults (AHRQ) · Nutritional Assessment (StatPearls) · Clinical Characteristics of Malnutrition (Academy of Nutrition and Dietetics/ASPEN) · Nursing Fundamentals 2e, 14.3 (Open RN) · Development of a Malnutrition Screening Tool (Nutrition) · Fundamentals of Nursing 21.4 Nutritional Assessment (OpenStax) · Visceral Proteins as Nutrition Markers (ASPEN) · Nutritional Assessment (Montgomery College) · Nursing Assistant, Ch. 7 (Open RN) · Vitamins (MedlinePlus) · Serum Albumin and Globulin (Clinical Methods) · Follow your facility's protocol for nutrition screening.
Nutritional Screening & Assessment
A malnourished patient can look well-nourished on paper if you skip the right screening tool. Knowing which tool to use — and when — changes outcomes before a single calorie is ordered.
Nutritional screening is a rapid, standardized process completed within 24 hours of admission to identify patients at nutritional risk. It is NOT a full assessment — it triages who needs one. Validated screening tools include the Malnutrition Screening Tool (MST), which asks about recent unintentional weight loss and appetite changes, and the Nutrition Risk Screening (NRS-2002) for hospitalized adults. A positive screen triggers a comprehensive nutritional assessment performed by or in collaboration with a registered dietitian. The full assessment includes anthropometric data (BMI, mid-arm circumference, waist-to-hip ratio), biochemical markers (albumin, prealbumin, transferrin), clinical exam (skin turgor, hair quality, wound healing, oral mucosa), and dietary history (24-hour recall, food frequency, intake adequacy). Prealbumin (normal 15–36 mg/dL, half-life ~2 days) reflects recent protein status far better than albumin (normal 3.5–5.0 g/dL, half-life ~20 days), which lags behind actual changes. The nurse's role is to perform the initial screen, collect accurate intake and output, obtain daily weights on the same scale at the same time in similar clothing, and communicate findings to the interdisciplinary team.
Key Distinctions
Don't confuse screening (quick, nurse-driven, identifies risk) with assessment (comprehensive, dietitian-involved, diagnoses the problem). Students mix up albumin and prealbumin — albumin reflects chronic status over weeks; prealbumin tracks acute changes over days. A low albumin can also reflect inflammation or fluid overload, not just poor nutrition — it's not a standalone marker.
Clinical Pearl
Screen first, assess second. Prealbumin is the short game (days), albumin is the long game (weeks) — pick the right lab for the right question.
Knowledge Check
3 quick questions on the must-knows for this topic.
Nutritional screening should be completed within what window of admission?
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