Editing Nutrition (section)

== Nutrition-Related Laboratory Values ==

{| class="wikitable"
! Test !! Typical adult reference range !! Nutritional significance
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| Albumin || 3.5 to 5.0 g/dL || Half-life about 18 to 21 days, so it reflects long-standing status. Falsely low with inflammation, liver disease, nephrotic syndrome, and fluid overload; falsely high with dehydration. It is better understood as an inflammation marker than a pure nutrition marker.
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| Prealbumin (transthyretin) || 15 to 36 mg/dL || Half-life 2 to 3 days, so it responds quickly and is used to track short-term response to nutrition support. Also depressed by inflammation.
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| Transferrin || 200 to 400 mg/dL || Half-life 8 to 10 days; also rises in iron deficiency, which confounds interpretation.
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| Total lymphocyte count || 1500 to 3000 cells/mm³ || Falls with protein-energy malnutrition; reflects immune competence.
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| Hemoglobin || 14 to 18 g/dL (male), 12 to 16 g/dL (female) || Low in iron, B12, and folate deficiency
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| Hematocrit || 42 to 52 percent (male), 37 to 47 percent (female) || Elevated with dehydration, low with anemia and overhydration
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| Serum iron and ferritin || Ferritin 12 to 300 ng/mL (varies by sex and lab) || Ferritin is the best indicator of iron stores but is an acute phase reactant and rises with inflammation
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| BUN || 10 to 20 mg/dL || Rises with high protein intake, dehydration, and gastrointestinal bleeding; falls with low protein intake and liver failure
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| Creatinine || 0.6 to 1.2 mg/dL || Reflects renal function and muscle mass
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| Serum sodium || 135 to 145 mEq/L || Reflects water balance more than salt intake
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| Serum potassium || 3.5 to 5.0 mEq/L || Critical for renal and diuretic-treated patients
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| Serum phosphorus || 3.0 to 4.5 mg/dL || Falls sharply in refeeding syndrome; rises in chronic kidney disease
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| Serum magnesium || 1.3 to 2.1 mEq/L || Falls in refeeding syndrome, alcohol use disorder, and diuretic therapy
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| Total calcium || 9.0 to 10.5 mg/dL || Interpret against albumin; low albumin falsely lowers total calcium while ionized calcium stays normal
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| Fasting glucose || 70 to 99 mg/dL || 100 to 125 mg/dL is prediabetes; 126 mg/dL or higher on two occasions is diabetes
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| Hemoglobin A1C || Below 5.7 percent normal || 5.7 to 6.4 percent prediabetes; 6.5 percent or higher diabetes. A common treatment goal is below 7 percent, individualized.
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| Total cholesterol || Below 200 mg/dL desirable || Screening lipid marker
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| LDL cholesterol || Below 100 mg/dL optimal || Below 70 mg/dL for very high cardiovascular risk
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| HDL cholesterol || Above 40 mg/dL (male), above 50 mg/dL (female) || Higher is protective
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| Triglycerides || Below 150 mg/dL || Responsive to alcohol, simple sugars, and weight; monitored during lipid infusion in parenteral nutrition
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'''Nursing application:''' Prealbumin, not albumin, is the value to trend when evaluating whether a patient is responding to nutrition support over the course of a week. Both must be interpreted alongside C-reactive protein or clinical inflammation, because acute illness suppresses both independent of intake.