What lab tests should be done to assess the nutritional status of a hospitalized, malnourished patient with a non-healing surgical wound?

Laboratory Tests for Nutritional Assessment in a Hospitalized, Malnourished Patient with a Non-Healing Surgical Wound

For hospitalized, malnourished patients with non-healing surgical wounds, a comprehensive nutritional assessment should include serum albumin, prealbumin, and absolute lymphocyte count as these have been shown to accurately predict postoperative complications and wound healing outcomes. 1

Core Laboratory Tests

• Serum albumin: While recent data suggests limitations as a malnutrition definer, it remains an important marker associated with nutrition risk and can predict postoperative complications 1
• Prealbumin (transthyretin): Preferred over albumin due to its shorter half-life that better reflects acute changes in nutritional status 1
• Absolute lymphocyte count: Along with serum albumin and SGA, this has been shown to accurately predict postoperative complications after abdominal surgery 1
• C-reactive protein (CRP): Important to measure inflammation which affects interpretation of other nutritional markers 1

Important Considerations for Laboratory Interpretation

• Albumin and prealbumin are negative acute phase reactants and decrease during inflammation, making them unreliable markers of nutritional status in acute inflammatory conditions 1
• In critically ill patients, trauma patients, or those with significant inflammation, albumin and prealbumin will decrease regardless of nutritional status 1
• Laboratory values should be interpreted alongside validated nutritional screening tools rather than in isolation 1

Validated Nutritional Screening Tools to Complement Laboratory Tests

• Nutritional Risk Screening (NRS-2002): Endorsed by both ESPEN and ASPEN for hospitalized patients, includes BMI, weight loss, food intake, and disease severity 1
• Subjective Global Assessment (SGA): Incorporates weight change, dietary intake, GI symptoms, functional capacity, and physical examination 1
• Nutrition Risk Index (NRI): Incorporates serum albumin and weight loss ratio, particularly validated in cancer patients 1

Monitoring Food Intake

• Food intake should be monitored daily in malnourished patients using semi-quantitative methods 1
• Insufficient food intake equal to or less than 50% of energy requirements over 3 days should trigger nutritional intervention 1
• Reduced food intake is one of the five criteria used in the Global Leadership Initiative on Malnutrition (GLIM) approach to diagnosing malnutrition 1

Additional Considerations for Patients with Non-Healing Wounds

• Malnutrition contributes to an immunocompromised system, reduced collagen synthesis, and diminished tensile strength during the wound healing process 2
• Malnourished patients have longer hospital stays, altered immune function, and impaired skin integrity and wound healing 3
• Patients with non-healing wounds may require additional protein supplementation to prevent further muscle loss 4, 2

Pitfalls to Avoid

• Do not rely solely on BMI, midarm circumference, or tissue skinfold thickness as these may not correlate with postoperative complication risk 1
• Avoid interpreting albumin or prealbumin in isolation without considering the patient's inflammatory status 1
• Remember that malnutrition is often under-recognized and inadequately managed in hospitalized patients, leading to higher rates of complications such as pressure injuries and delayed wound healing 3, 5
• Don't wait for laboratory confirmation to begin nutritional support if clinical signs of malnutrition are present 1

By implementing comprehensive nutritional assessment including these laboratory tests and screening tools, clinicians can better identify and address malnutrition in hospitalized patients with non-healing surgical wounds, potentially improving wound healing outcomes and reducing complications.