From the Guidelines
Protein-Calorie Malnutrition (PCM) is objectively diagnosed by signs including visible muscle wasting, low body mass index (BMI) below 18.5 kg/m², loss of subcutaneous fat, and edema, as well as laboratory findings such as decreased serum albumin, prealbumin, transferrin, and total lymphocyte count, as defined by the European Society for Clinical Nutrition and Metabolism (ESPEN) criteria 1. The ESPEN criteria, as summarized in a 2017 study published in Clinical Nutrition 1, define malnutrition as a state resulting from lack of intake or uptake of nutrition that leads to altered body composition and body cell mass, leading to diminished physical and mental function and impaired clinical outcome from disease. Key diagnostic criteria for malnutrition include:
- Reduced body mass index (BMI) <18.5 kg/m2
- Combined weight loss and reduced BMI (age-dependent cut-offs)
- Reduced gender-dependent fat free mass index (FFMI) A more recent study published in Advances in Nutrition in 2025 1 highlights the importance of nutritional risk screening tools, such as the Nutritional Risk Screening (NRS)-2002, Subjective Global Assessment (SGA), Nutrition Risk Index, and Perioperative Nutrition Score, in identifying patients at risk of malnutrition. The study also notes that the Global Leadership Initiative on Malnutrition developed a 2-step approach for diagnosing malnutrition, which involves identification of at-risk patients using any validated screening tool, and assessment and grading of malnutrition severity via phenotypic and etiologic criteria 1. The most recent and highest quality study, published in 2025 1, supports the use of these criteria and tools in diagnosing malnutrition, and highlights the importance of early identification and intervention to prevent malnutrition-related complications and improve patient outcomes. Some of the key physical manifestations of PCM include:
- Visible muscle wasting, particularly in the temporal region, deltoids, and interosseous muscles of the hands
- Loss of subcutaneous fat
- Edema, which may mask true weight loss
- Skin changes, such as dry, flaky skin, poor wound healing, and hair that becomes thin, sparse, and easily pluckable
- Laboratory findings, such as decreased serum albumin (below 3.5 g/dL), prealbumin, transferrin, and total lymphocyte count.
From the Research
Objective Signs of Protein-Calorie Malnutrition (PCM)
The objective signs of Protein-Calorie Malnutrition (PCM) can be identified through various methods, including:
- Anthropometric measurements, such as body weight, triceps skinfold thickness (TSF), and midarm circumference (MAC) 2
- Laboratorial examinations, including serum albumin, hemoglobin, and peripheral blood lymphocytes 2
- Nutrition-focused physical examination (NFPE), which evaluates muscle mass, fat stores, fluid retention, micronutrient deficiencies, and functional capacity 3
- Signs of vitamin and mineral deficiencies, and reduced physical activity 3
Specific Indicators of PCM
Specific indicators of PCM include:
- Hypoalbuminemia (< 3.5 g/dL) 2
- Loss of TSF (< 10 mm) and MAC (< 23.3 cm) 2
- Obvious significant muscle wasting, and loss of subcutaneous fat 4
- Weight loss of >2% in 1 week, 5% in 1 month, or 7.5% in 3 months 4
- Bedridden or otherwise significantly reduced functional capacity 4
Diagnosis and Assessment of PCM
The diagnosis and assessment of PCM can be made using various tools, including: