3.5 Screening & Life-Cycle Assessment

Screening vs. Assessment

Nutrition screening is a quick process — often performed by nursing or support staff — to identify patients who may be at nutrition risk and need referral to the RD. It is not part of the four-step NCP and does not produce a diagnosis. The Joint Commission requires a nutrition screen within 24 hours of inpatient admission. The exam tests this boundary: anyone can screen, but only the RD assesses and diagnoses.

Validated adult screening tools include:

A positive screen triggers referral; it never substitutes for the full ABCD assessment. The defining features of a good screening tool are that it is quick, low-cost, sensitive, and usable by non-dietitians — which is exactly why screening is delegated and assessment is reserved for the RD. If an exam stem asks who may perform a step, screening can be done by nursing or even a trained aide, but only the RD performs assessment, writes the nutrition diagnosis, and orders the nutrition intervention.

Diagnosing Malnutrition (AND/ASPEN)

The Academy of Nutrition and Dietetics (AND) and the American Society for Parenteral and Enteral Nutrition (ASPEN) consensus requires at least two of six characteristics to diagnose malnutrition:

1. Insufficient energy intake
2. Unintentional weight loss
3. Loss of muscle mass
4. Loss of subcutaneous fat
5. Localized or generalized fluid accumulation (may mask weight loss)
6. Diminished functional status (e.g., reduced handgrip strength)

Severity is then classified as non-severe (moderate) vs. severe, and context as acute illness/injury, chronic illness, or social/environmental circumstances. The newer GLIM (Global Leadership Initiative on Malnutrition) criteria require one phenotypic criterion (weight loss, low BMI, or reduced muscle mass) plus one etiologic criterion (reduced intake/absorption or disease-related inflammation). On the exam, count the characteristics in the stem — two or more meets criteria, and no separate medical diagnosis is required for the RD to make the call.

Severity grading rides on the degree of each finding, not just its presence. For example, in the context of acute illness, >2% weight loss in one week, >5% in one month, or >7.5% in three months supports severe malnutrition, whereas smaller losses over the same windows support non-severe. Likewise, energy intake at ≤50% of estimated needs for ≥5 days flags severe in acute illness. The exam may give you the percentage and the timeframe and ask you to grade severity, so memorize that thresholds tighten as the illness becomes more acute and loosen for chronic and social/environmental contexts.

Life-Cycle: Pregnancy

Energy and several micronutrient needs rise during pregnancy, and these specific numbers are frequently tested:

The first trimester adds no extra energy — a classic trap, since many candidates assume eating increases from conception. Recommended gestational weight gain depends on prepregnancy BMI per the Institute of Medicine: 28-40 lb if underweight, 25-35 lb if normal weight, 15-25 lb if overweight, and 11-20 lb if obese. Folic acid before and during early pregnancy reduces neural tube defects, which is why supplementation is emphasized periconceptionally.

Life-Cycle: Pediatric and Geriatric

Pediatric

Assessment centers on growth charts and percentiles rather than adult BMI categories. Use WHO growth charts for children under 2 and CDC charts for ages 2 and older. Plotting weight-for-age, length/height-for-age, and BMI-for-age over time detects faltering growth (failure to thrive) or excess gain — a single point matters far less than the trend and whether the child is crossing percentile lines. Energy is estimated with age- and weight-specific equations (the DRI Estimated Energy Requirement, EER) and per-kg rules that run well above adult values.

Geriatric

Older adults face sarcopenia, dehydration, polypharmacy, dysphagia, and social isolation. The Mini Nutritional Assessment (MNA) is the validated geriatric screening/assessment tool. Protein needs often rise to 1.0-1.2 g/kg/day (higher than the adult RDA of 0.8) to preserve muscle, and fluid status needs close monitoring because the thirst response and renal concentrating ability both decline with age. Always reconcile medications, since many alter appetite, taste, or nutrient absorption.

Two more life-cycle facts round out high-yield testing. In lactation, energy rises by roughly +330-400 kcal/day above non-pregnant needs, and fluid demand increases to support milk volume. In infancy, energy needs per kilogram are the highest of any life stage (≈100-110 kcal/kg/day in early infancy), human milk or iron-fortified formula is the sole recommended nutrition for about the first six months, and complementary foods begin around six months.

When a stem moves across the lifespan, anchor on the principle that per-kilogram needs are highest in infancy, taper through childhood, and that protein-per-kilogram targets rise again in older adulthood to defend against sarcopenia.