Registered Nurses' Association of Ontario

Nursing Best Practice Guidelines

Nutrition/Hydration-Related Blood Work

Albumin and Prealbumin
Albumin and prealbumin are hepatic proteins that are often cited in the literature as markers of protein and nutrition status. There is much discussion among clinicians and authors, with many disputing the value of albumin and prealbumin as nutritional markers, especially in critical care and acute care settings. Low values reflect severity of illness and/or injury regardless of protein status and are “red flags” for the potential of a patient to develop malnutrition or to become more malnourished (Barnes et al., 2007; Fuhrman, Charney & Mueller, 2004).
If a patient presents with anemia it is imperative that the type of anemia be identified. Both iron deficiency anemia and anemia of chronic disease (ACD) result in a decreased hemoglobin level, which is a barrier to healing. A chronic non-healing pressure ulcer itself is an inflammatory process that may lead to ACD (Holcomb, 2001; Keast & Fraser, 2004).
Glycemic Control
The physical signs and symptoms of diabetes do not always accompany hyperglycemia that is identified by blood tests (Fraser, 2007). It is recommended that both fasting blood glucose and Hemoglobin A1C be screened in all individuals with pressure ulcers, as an individual may present with normal fasting levels but have impaired glucose tolerance. Screening an individual who has no known history of diabetes mellitus may uncover previously unidentified hyperglycemia that is negatively impacting his or her wound management. Preventing and treating ulcers are more effective when screening and management measures are implemented to address underlying factors such as hyperglycemia that impede successful outcomes. Hemoglobin A1C levels greater than 7.0 per cent (0.070) are associated with significantly increased risk for both microvascular and macrovascular complications (Canadian Diabetes Association Expert Committee, 2003). Individuals with diabetes exhibit significantly impaired wound healing and increased complication rates (Arnold & Barbul, 2006; Collins, 2003; Lioupis, 2005). Controlling serum glucose levels to promote wound healing and prevention cannot be overemphasized (Marston, 2006).
Hypothyroidism is a metabolic disorder that exerts biochemical and histological effects on tissue integrity and regeneration that can adversely affect wound prevention and healing (Ekmekzoglou & Zografos, 2006). Hypothyroidism and diabetes mellitus can coexist in clinical settings. The influence of these conditions individually and concurrently warrants the screening for, and immediate management of these conditions for optimal wound healing (Ekmekzoglou & Zografos, 2006).
Dehydration is a risk factor for skin breakdown and wound healing. The blood urea nitrogen (BUN):creatinine ratio may be used as an indicator of a patient’s hydration status, though may not be accurate in patients with renal failure. An elevated BUN level with a normal or low creatinine level may indicate under-hydration. A BUN:creatinine ratio greater than 20:1 is a red flag for dehydration which must be investigated and addressed. In addition, BUN and creatinine are indicators of renal function. A clinician must be aware of a patient’s renal status prior to the recommendation of enhanced protein, fluid, vitamins and minerals as there are precautions and contraindications to supplementation in a case of renal insufficiency as well as in other co-morbidities.