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Nutrition assessment reviews data for factors that affect nutritional and health status. Nutrition screening is the process of identifying characteristics known to be asso- ciated with nutrition problems. Historically, nutrition screening and assessment have primarily emphasized anthropometric data and dietary intake, especially in nursing facilities. However, laboratory assessment is an essential tool to assess nutritional status, to evaluate nutrition intervention programs, and to predict medical outcomes (1).

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National trends indicate that a declining number of laboratory tests are being ordered in all areas of health care. This trend is a reflection of cost-reduction pro- grams nationwide. Assessment of physical and nutri- tional status is done primarily through physical assessment and observed dietary intake. Clinical signs and symptoms must be identified in order to justify the request for laboratory tests. Facility protocols or clini- cal pathways form the infrastructure for ordering more laboratory tests.

IMPLICATIONS OF SELECTED LABORATORY TESTS

All requests for laboratory tests must be justified by the health care team. Remember that one test from a labo- ratory cannot evaluate a client’s short-term response to medical nutrition therapy (MNT). Further, all tests are not appropriate for all clients. For example, “creatinine excretion cannot be used to evaluate muscle mass in patients/residents with renal failure because the test assumes normal renal function.” Remember to con- sider the overall medical condition of older adults and current pharmacological intervention strategies in the interpretation of laboratory tests (1).

CHANGES IN NUTRITIONAL STATUS One laboratory test may or may not reflect improved nutritional status once an MNT intervention program has begun. Hydration status significantly impacts

Laboratory Assessment

laboratory results and is commonly overlooked (2). To evaluate hydration status, a variety of laboratory tests, recent dietary history, and physical assessment will need to be used. Table 16.1 lists laboratory tests that can be used to evaluate hydration status (1). As the older adult’s hydration and dietary intake changes, more than one laboratory test will be required to accu- rately document changes in nutritional status. A review of support data, such as physical findings, changes in anthropometric data, reported symptoms, and nutrition intake, will increase confidence in laboratory results (3).

EFFECT OF STRESS

When interpreting laboratory test results, one must consider the effect stress has on the older adult. A change in laboratory values is often seen in those who have short-term emotional stress, physical stress from surgery, or an infection. For example, an unexpected hospitalization of an older adult because of a fall “may result in an elevated fasting blood glucose. Two fasting blood glucose levels above 126 mg/dL are the criteria for a diagnosis of non-insulin-dependent diabetes” (4). If the elevated fasting blood glucose is due to stress, it will return to normal once the stressful situation is resolved (5). Unfortunately, some older adults are not reevaluated after an appropriate time interval and will have a diagnosis of non-insulin-dependent diabetes as a permanent part of their medical records.

EFFECT OF OTHER MEDICAL INTERVENTIONS

Laboratory tests done before admission to an extend- ed-care facility may not reflect the true nutritional status of an older adult. For example, if a hospitalized older adult has a very poor iron status, he or she might receive a blood transfusion to improve the iron status in order to shorten the length of stay in the hospital. However, the laboratory tests taken after the blood