Nutritional Status & Lab Analysis

• Biochemical assessment involves analyzing patient specimens and comparing these to reference standards.

Advantages of Biochemical Assessment

• Routine lab data is readily available in medical records.
• It provides an objective measure for nutrition assessment.

Limitations of Biochemical Assessment

• Biochemical assessments may not offer specific evidence of nutrition status.
• Normal ranges in lab results can differ based on factors such as age, sex, and pregnancy.
• Disease state or condition and lab differences can contribute to result variations.

Additional Considerations for Biochemical Assessment

• Serial measures, taken over a time series, are more informative than single data points.
• Treat the patient's overall condition and health, rather than relying solely on lab values.
• Clinical improvements do not always correlate with improvements in lab results.
• Tissue stores of micronutrients are a more direct and relevant indicator of nutrition status compared to blood values.

Types of Specimens Used

• Whole blood is collected with an anti-coagulant and contains red blood cells, white blood cells, and platelets.
• Serum is a fluid obtained after blood is clotted, and the clot is removed, and it does not contain red or white blood cells.
• Plasma includes serum plus fibrinogen and is the transparent liquid component of blood collected in tubes with an anti-coagulant such as heparin.
• Urine contains excreted metabolites.
• Stool can aid in determining malabsorption.
• Other specimens include breath, saliva, and sweat.

Clinical Chemistry Panels

• The basic metabolic panel (BMP) includes eight tests: glucose, calcium, sodium, potassium, CO2, chloride, BUN, and creatinine.
• Chem 7 is the same as BMP but does not include calcium.
• Comprehensive metabolic panel (CMP) includes BMP in addition to albumin, total protein, alkaline phosphatase (ALP), alanine amino-transferase (ALT), aspartate amino-transferase (AST), and bilirubin.
• Chem-20 comprises CMP + GGT, LDH, cholesterol, and uric acid.
• Complete blood count involves counting the cells in the blood.

Serum Electrolytes Overview

• Serum electrolytes, including sodium (Na), potassium (K), chloride (Cl), calcium (Ca), phosphorus (Phos), CO2, and HCO3, are monitored in nutrition support patients, as well as those with kidney disease, pulmonary disease, alkalosis, or acidosis.
• Normal ranges are: Na 136-145 mEq/L, K 3.5-5.5 mEq/L, and Cl 95-105 mEq/L.

Sodium Serum Electrolytes

• Hyponatremia means low sodium, and hypernatremia means high sodium.
• These reflect issues with sodium concentration and total-body water.
• Sodium typically increases in cases of hypovolemia/dehydration and typically decreases with hypervolemia.
• Sodium levels may be normal or increased in certain conditions.

Serum Electrolytes: Potassium

• Potassium (K) is a major intracellular cation, but serum levels do not correlate with body stores.

Hypokalemia

• Hypokalemia is low potassium and can be caused by GI losses like diarrhea and vomiting, medications, and refeeding syndrome.

Hyperkalemia

• Hyperkalemia is high potassium and can be caused by kidney or renal failure and medications.

Calcium Serum Electrolytes

• Normal calcium levels are between 8.5-10.5 mg/dl, but calcium does not correlate well with body stores.
• Increased calcium may indicate a vitamin D deficiency; decreased may correlate to kidney disease or hypoparathyroidism.

Phosphorus Serum Electrolytes

• Normal phosphorus levels are between 3-4.5 mg/dl.
• Increased phosphorus may indicate hypoparathyroidism, chronic antacid ingestion, or kidney disease.
• Decreased phosphorus may indicate vitamin D deficiencies or refeeding syndrome.

Blood Proteins Overview

• Blood proteins refer to albumin, transferrin, and pre-albumin.

Albumin

• Normal albumin levels are between 3.5-5 mg/dl.
• Decreases in albumin may mean liver disease or acute inflammatory diseases; however, levels are often normal in unstressed starvation due to reduced catabolism.

Transferrin

• Normal transferrin levels are between 200-400 mg/dl.
• Transferrin binds and transports iron, and is inversely correlated with body iron stores.
• Elevations in transferrin may be an early sign of iron deficiency, and levels greater than 100 mg/dl mean severe depletion.
• Liver disease and zinc deficiency can decrease transferrin levels.

Prealbumin

• Normal prealbumin levels are between 16-40 mg/dl.
• Prealbumin is a carrier for thyroxin and an acute phase response, and hyperthyroidism may decrease it.

Indicators of Acute Inflammation

• C-reactive protein is an inflammatory biomarker for acute inflammation, and it may increase above 10 mg/dl in acute infection or stress.
• High-sensitivity CRP is an inflammatory biomarker for chronic, lower-level inflammation, and levels are measured between 0-10 mg/dl.

Acute Phase Reactants Response

• The body mounts an inflammatory response when someone becomes acutely ill or is injured, resulting in the release of cytokines.
• Positive acute phase reactants/proteins, like CRP, increase rapidly.
• Negative acute phase reactants/proteins, like albumin, PAB, transferrin, and RBP, may rapidly decline in circulation
• Hyper-metabolic pathways are up-regulated.

Acute Phase Proteins

• Acute phase proteins include albumin, pre-albumin, retinol binding protein, and transferrin.
• A problem can arise with using these to assess malnutrition in the hospital.

Glucose Indicators

• Normal glucose levels are between 70-99 mg/dl.
• Glucose may be used to diagnose diabetes and is monitored in nutrition support patients and those with diabetes.

Fasting Glucose Thresholds

• 100-125 mg/dl indicates possible prediabetes.
• 126 mg/dl or higher indicates of diabetes.

Hemoglobin A1c

• Hemoglobin A1c is normally less than 5.5%.
• 5.5-6.4% indicates a high risk for prediabetes.
• 6.5% or higher diagnosis for diabetes.
• An A1c level of 7 has an average glucose equivalent of 154 mg/dl
• An A1c level of 9 has an average glucose equivalent of 212 mg/dl
• An A1c level of 12 has an average glucose equivalent of 298 mg/dl

Kidney Function Indicators

• Creatinine, with normal levels between 0.6-1.2mg/dL increases in kidney disease and decreases in malnutrition.
• BUN, with normal levels between 6-20 mg/dL increases in renal disease and protein catabolism.
• BUN may increase with dehydration/hypovolemia and decrease with hypervolemia/overhydration.

Liver Function Indicators

• Normal Bilirubin levels are between 0.3-1 mg/dl.
• Increased bilirubin means liver disease, hemolysis, or some anemias.
• AST/SGOT, with normal levels between 8-33, helps the body break down amino acids, and higher levels can indicate liver or muscle breakdown.
• ALT/SGPT, with normal levels between 4-36, helps the body convert proteins into energy for liver cells, and higher levels indicate liver damage.
• Alkaline Phosphatase, with normal levels between 44-147 IU/L, is an enzyme found in the liver and bone that helps break down proteins.

Alkaline Phosphatase

• Elevated levels of alkaline phosphatase may indicate liver disease or growth in children.

Lipid Status Overview

• Lipid status is determined by total cholesterol, LDL cholesterol, and triglycerides.

Total Cholesterol

• Levels of total cholesterol of less than 200 mg/dl are desirable.
• Lowered levels may mean malnutrition, and levels of 240 mg/dl or greater are high.

LDL Cholesterol

• Levels of LDL cholesterol of less than 100 mg/dl are desirable.
• LDL cholesterol is most closely related to death/MI.
• Levels of LDL cholesterol between 130-159 mg/dl are borderline high, levels between 160-189 mg/dl are high, and levels of 190 mg/dl or greater are very high.

Triglycerides

• Levels of triglycerides of less than 150 mg/dl are desirable.
• Elevated triglycerides could mean glucose intolerance or diabetes and may occur in non-fasting states, and levels between 200-499 mg/dl are considered high.

Anemia Indicators

• Anemia is a condition of low availability of red-blood cells.
• Nutritional anemias are caused by nutritional deficiencies.
• For hemoglobin and hematocrit, normal hemoglobin levels are 12-16 g/dL for females and 14-18 g/dL for males.

Hemoglobin

• Hemoglobin is a protein in erythrocytes that delivers O2 and picks up CO2.
• Hematocrit is the percent of blood composed of RBCs, and it may decrease in iron-deficiency anemia, hemorrhage, marrow failure, kidney disease, or malnutrition.

MCV and MCH Indicators

• Normal MCV levels are between 80-99 fl, and normal MCH levels are between 27-31 pg/cell.
• Mean corpuscular volume (MCV) indicates the size of red blood cells.
• Mean corpuscular hemoglobin (MCH) estimates the amount of hemoglobin in each red blood cell.
• If MCV is normal and hemoglobin and hematocrit are low, this may indicate normocytic anemia.
• If MCV is decreased and hemoglobin and hematocrit are low, the most likely cause is iron deficiency.
• If MCV is increased and hemoglobin and hematocrit are low, the most likely cause is B-12 or folate deficiency.

Anemia Classification

• Hematocrit and hemoglobin indicate anemia but are not specific to iron-deficiency anemia.
• Decreased MCV means microcytic anemia, and increased MCV means macrocytic anemia.
• Leukocyte, reticulocyte, and platelet counts help differentiate non-nutritional anemias.

Macrocytic Anemia

• Macrocytic anemia may be associated with B Vitamin deficiencies.
• Megaloblastic anemia comes from folate or B-12 deficiency.
• RBC folate is a superior indicator of folate status.
• Folate status is affected by bariatric surgery, CD, anti-convulsants, and ETOH abuse.
• Pernicious anemia is a vitamin B12 deficiency due to an absence of intrinsic factor.

Pernicious Anemia

• Pernicious anemia is due to stomach lining atrophy and inflammation, and serum vitamin B12, serum, or urine methylmalonic acid can measure it.

Exploring Anemia Further

• If hemoglobin and hematocrit and MCV are low, check serum Ferritin.
• Ferritin less than 10 ng/100 is diagnostic of iron-deficiency anemia.
• If hemoglobin and hematocrit are low and MCV is high, check B-12, folate, and serum methylmalonic acid.
• Increased MMA with low B-12 means a B-12 deficiency is likely.

Deficiency Assessment

• If intrinsic factor deficit is the most likely cause, check IF.
• If folate is decreased, especially with increased serum homocysteine, folate deficiency is the most likely cause.
• If folate and B12 are normal and homocysteine is low, low B-6 may be a cause.

Hydration Status

• Hydration status can be measured by markers such as serum sodium, BUN, serum osmolality and urine specific gravity
• Clinical data, history, and physical examination are needed to make a diagnosis

Hypovolemia and Dehydration

• Hypovolemia, or dehydration, is a stage of negative fluid balance caused by decreased intake or increased fluid losses and shifts.
• Hypervolemia, or over-hydration, shows an increase in extracellular fluid volume and is caused by increased capillary hydrostatic pressure, decreased colloid osmotic pressure, physical inactivity, and over-drinking.

Serum Osmolality

• Typically serum osmolality increases with hypovolemia but may sometimes be decreased or normal
• Usually serum osmolality decreases with hypervolemia but may be increased or normal

Urine Specifc Gravity

• Urine specific gravity generally increases with hypovolemia and decreases with hypervolemia.

Urine Osmolality

• Urine osmolality is increased with hypovolemia and decreased with hypervolemia.

Biochemical Analysis

• Biochemical analysis can be used in combination with other assessment data to assess nutrition status, though biochemical indicators are often non-specific for nutrient deficiency.
• Creatinine, formed at a constant rate from creatine phosphate in muscle tissue and a by-product of creatine de-phosphorylation, is sometimes used to assess somatic protein status.

Creatinine Levels

• Eating lots of meat can increase creatinine levels.
• Increased creatinine also shows up in muscle injury, the latter half of the menstrual cycle, sepsis, and trauma.
• Biochemical assessment depends on combination with other assessment data.
• It cannot identify malnutrition using only biochemical analysis.

Explore micronutrient deficiencies, malabsorption, and electrolyte imbalances. Understand serum vs. plasma specimens, iron deficiency detection, and conditions leading to hypernatremia. Evaluate CRP levels and their implications.