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Part II Nutrition Assessment, Consequences, and Implications Nutritional Significance

Creatinine is a by-product of the metabolism of muscle creatinine phosphate to form adenosine triphosphate (ATP). It is produced at a constant rate determined by the individual’s muscle mass and kidney’s excretory function. Often creatinine levels are slightly lower in older adults because of decreased muscle mass (1). An elevated creatinine level suggests rapid muscle loss from trauma or surgery. Elevated levels also indi- cate possible renal failure. Critical values above 4 mg/dL indicate serious impairment in renal function. However, a normal creatinine does not always mean unimpaired renal function. Creatinine level is inter- preted in conjunction with BUN. Unlike the BUN, cre- atinine is not significantly affected by dehydration, malnutrition, or hepatic function (1). Hydration status can be evaluated using the BUN:creatinine ratio. The normal ratio is 10:1. Ratios higher than 25 suggest dehydration; ratios lower than 10 suggest overhydration (1). Creatinine levels increase with (1):

● ● ● ● ● ●

rapid muscle loss surgery, trauma

impaired renal function azotemia

chronic nephritis

obstruction of urinary tract ● reduced renal blood flow shock, dehydration

●

● CHF ●

● diabetes rhabdomyolysis

Creatinine levels decrease with: ●

●

muscular dystrophy debilitation.

The following drugs may increase creatinine levels: ●

cimetidine ● ●

aminoglycosides cephalosporins

● heavy metal chemotherapeutic agents Folate

Normal Values ●

●

5 to 25 ng/mL; 11 to 57 nmol/L (SI) (5) Nutritional Significance

Folate levels are used to evaluate hemolytic disorders and to detect megaloblastic anemia. Decreased folate

levels are associated with megaloblastic anemia, hemolytic anemia, malnutrition, malabsorption syn- dromes, liver disease, and celiac disease. Elevated levels are often seen in pernicious anemia (1). Folate supplementation may mask a B-12 defi- ciency; however, the level at which this occurs is not well documented. Recent studies using folate supple- ments to reduce elevated homocysteine levels recom- mend supplementing B-12 when a folate supplement is ordered (1).

Folate levels increase with (1): ●

●

pernicious anemia vegetarianism

Folate levels decrease with (1): ●

megaloblastic anemia ● hemolytic anemia

protein-energy malnutrition ● malabsorption syndromes cancer

● ● ● ●

alcoholism liver disease

The following drugs may decrease folate levels (1): ●

alcohol ● ● ● ● ● ● ● ● ● ● aminopterin

aminosalicylic acid ampicillin

antimalarials

ahloramphenicol erythromycin estrogens

methotrexate penicillin

mhenobarbital

● mhenytoin tetracycline

● Glucose, Blood

Normal Values ●

Adults: 70 to 100 mg/dL; 3.9 to 5.5 mmol/L (SI) (5)

Older adults: increased slightly (5)

Critical Values ●

●

400 mg/dL (renal threshold is about 180 mg/dL) (5)

Less than 50 mg/dL in men; less than 40 mg/dL in women (5)