Clinical Chemistry Panels
Historically the majority of laboratory tests were ordered as panels or groupings; however, the current practice is that the professional ordering the test must justify the medical need for each test ordered. The bundling or grouping of laboratory tests is changing as health care reforms reshape medical prac- tices to be more cost effective. The most commonly ordered groups of tests are the basic metabolic panel (BMP) and the comprehensive metabolic panel (CMP) that include groups of laboratory tests defined by the Centers for Medicare and Medicaid Services for reimbursement purposes. The BMP and CMP require the patient to fast for 10 to 12 hours before test- ing. The BMP includes eight tests used for screening blood glucose level, electrolyte and fluid balance, and kidney func- tion. The CMP includes all the tests in the BMP and six ad- ditional tests to evaluate liver function. Table 7-1 explains these tests (see Appendix 22).
Analytes Reference Range* Purpose Significance
Basic Metabolic Panel (BMP) (All Tests Reflect Fasting State) Glucose 70-99 mg/dl; 3.9-5.5
mmol/L(fasting) Used to screen for diabetes and to mon- itor patients with diabetes. Individuals experiencing severe stress from inju- ries or surgery have hyperglycemia related to catecholamine release
Fasting glucose .125 mg/dl indicates DM (oral glucose tolerance tests are not needed for diagnosis); fasting glucose .100 mg/dl is indicator of insulin resistance Monitor levels along with triglycerides in those receiving
total parenteral nutrition for glucose intolerance Total calcium 8.5-10.5 mg/dl;
2.15-2.57 mmol/L Normal dependent on
albumin level
Reflects the calcium levels in the body that are not stored in bones. Used to evaluate parathyroid hormone func- tion, calcium metabolism and monitor patients with renal failure, renal trans- plant, and some cancers
Hypercalcemia associated with endocrine disorders, malignancy, and hypervitaminosis D
Hypocalcemia associated with vitamin D deficiency and inadequate hepatic or renal activation of vitamin D, hypoparathyroidism, magnesium deficiency, renal failure, and nephrotic syndrome
When serum albumin is low, ionized calcium is measured Na1 135-145 mEq/L† Reflects the relationship between total
body sodium and extracellular fluid volume as well as the balance between dietary intake and renal excretory function
Used in monitoring various patients, such as those receiv- ing total parenteral nutrition or who have renal condi- tions, uncontrolled DM, various endocrine disorders, as- citic and edematous symptoms, or acidotic or alkalotic conditions; water dysregulation, and diuretics. Increased with dehydration and decreased with overhydration
K1 3.6-5 mEq/L† Levels often change with sodium lev-
els. As sodium increases, potassium decreases and vice versa. Reflects kidney function, changes in blood pH, and adrenal gland function
Used in monitoring various patients, such as those receiv- ing total parenteral nutrition or who have renal condi- tions, uncontrolled DM, various endocrine disorders, as- citic and edematous symptoms, or acidotic or alkalotic conditions; decreased K1 associated with diarrhea, vom- iting, or nasogastric aspiration, water dysregulation, some drugs, licorice ingestion, and diuretics; increased K1 associated with renal diseases, crush injuries, infection, and hemolyzed blood specimens.
Cl2 101-111 mEq/L† Reflects acid-base balance, water
balance, and osmolality Used in monitoring various patients, such as those receiv- ing total parenteral nutrition or who have renal condi- tions, chronic obstructive pulmonary disease, diabetes insipidus, acidotic or alkalotic conditions; increased with dehydration and decreased with overhydration
HCO32 (or total CO2
21-31 mEq/L† Used to assess acid-base balance and
electrolyte status Used in monitoring various patients, such as those receiv- ing total parenteral nutrition or who have renal conditions, chronic obstructive pulmonary disease, uncontrolled DM, various endocrine disorders, ascitic and edematous symptoms, or acidotic or alkalotic conditions
TABLE 7-1 Constituents of the Basic Metabolic Panel and Comprehensive Metabolic Panel
http://internalmedicinebook.com
Complete Blood Count
The complete blood count (CBC) provides a count of the cells in the blood and description of the RBCs. A hemogram is a CBC with a white blood cell differential count (often called a differential or diff). Table 7-2 provides a list of the basic elements of the CBC and differential, with reference ranges and explanatory comments.
Stool Testing
Mucosal changes in the gastrointestinal (GI) tract are indicated by problems such as diarrhea and bloody or black stool. Tests may be done on a stool sample and can reveal excessive amounts of fat (an indication of malabsorption), the status of the GI flora, and the amounts and types of bacteria present in the gut.
Fecal samples may be tested for the presence of blood, patho- gens, and gut flora. The fecal occult blood test is ordered routinely for adults older than age 50 and younger adults with unexplained anemia. Stool culture testing may be ordered in patients with prolonged diarrhea, especially if foodborne illness is suspected. If pathogenic bacteria are isolated in stool culture,
appropriate pharmacologic interventions are initiated. Patients with chronic GI symptoms such as maldigestion or unexplained weight loss or gain may benefit from gut flora testing to identify pathologic flora or an imbalance of physiologic flora. In addi- tion, stool tests may be helpful to evaluate the gut microbiota and the effectiveness of probiotic, prebiotic, and synbiotic use.
Urinalysis
The urinalysis test is used as a screening or diagnostic tool to detect substances or cellular material in the urine associated with different metabolic and kidney disorders. Some urinalysis data have broader medical and nutritional significance (e.g., glycosuria suggests abnormal carbohydrate metabolism and possibly diabetes). The full urinalysis includes a record of (1) the appearance of the urine, (2) the results of basic tests done with chemically impregnated reagent strips (often called dipsticks) that can be read visually or by an automated reader, and (3) the microscopic examination of urine sediment.
Table 7-3 provides a list of the chemical tests performed in a urinalysis and their significance.
*Reference ranges may vary slightly among laboratories.
†mEq/L 5 1 mmol/L.
ALP, Alkaline phosphate; ALT, alanine aminotransferase; AST, aspartate aminotransferase; BUN, blood urea nitrogen; Cl2, chlorine; CO2, carbon dioxide; DM, diabetes mellitus; HCO32, bicarbonate; K1, potassium; Na1, sodium; PEM, protein-energy malnutrition.
Analytes Reference Range* Purpose Significance
Basic Metabolic Panel (BMP) (All Tests Reflect Fasting State) BUN or urea 5-20 mg urea nitrogen/dl
1.8-7 mmol/L Used to assess excretory function of
kidney and metabolic function of liver Increased in those with renal disease and excessive pro- tein catabolism and overhydration; decreased in those with liver failure and negative nitrogen balance and in females who are pregnant
Creatinine 0.6-1.2 mg/dl;
53-106 mmol/L (males) 0.5-1.1 mg/dl;
44-97 mmol/L (females)
Used to assess excretory function of
kidney Increased in those with renal disease and after trauma or surgery; and decreased in those with malnutrition (i.e., BUN/creatinine ratio .15:1)
Comprehensive Metabolic Panel (CMP) (All Tests Reflect Fasting State and Includes All of the Tests in the BMP and Six Additional Tests)
Albumin 3.5-5 mg/dl; 30-50 g/L Reflects severity of illness, inflamma- tory stress and serves as marker for mortality
Decreased in those with liver disease or acute inflamma- tory disease and overhydration. Increases with dehydra- tion. It is not a biomarker of protein status
Total protein 6.4-8.3 g/dl;64-83 g/L Reflects albumin and globulin in blood Not a useful measure of nutrition or protein status
ALP 30-120 units/L; 0.5-2
mKat/L Reflects function of liver; may be used
to screen for bone abnormalities Increased in those with any of a variety of malignant, muscle, bone, intestinal, and liver diseases or injuries
ALT 4-36 units/L at 37° C;
4-36 units/L
Reflects function of liver Used in monitoring liver function in those receiving parenteral nutrition
AST 0-35 IU/L; 0-0.58 mKat/L Reflects function of liver; may be used
to screen for cardiac abnormalities Used in monitoring liver function in those receiving parenteral nutrition
Bilirubin Total bilirubin 0.3-1 mg/dl;
5.1-17 mmol/L Indirect bilirubin 0.2-0.8
mg/dl; 3.4-12 mmol/L Direct bilirubin 0.1-0.3 mg/dl; 1.7-5.1 mmol/L
Reflects function of liver; also used to evaluate blood disorders, and biliary tract blockage
Increased in association with drugs, gallstones, and other biliary duct diseases; intravascular hemolysis and hepatic immaturity; decreased with some anemias
Phosphorous
(phosphate) 3-4.5 mg/dl; 0.97-1.45
mmol/L Hyperphosphatemia associated with hypoparathyroidism
and hypocalcemia; hypophosphatemia associated with hyperparathyroidism, chronic antacid ingestion, and renal failure
Total cholesterol ,200 mg/dl; 5.20 mmol/L Decreased in those with malnutrition, malabsorption, liver diseases, and hyperthyroidism
Triglycerides ,100 mg/dl; ,1.13 mmol/L (age and gender dependent)
Increased in those with glucose intolerance (e.g., in those receiving parenteral nutrition who have combined hyper- lipidemia) or in those who are not fasting
TABLE 7-1 Constituents of the Basic Metabolic Panel and Comprehensive Metabolic Panel—cont’d
http://internalmedicinebook.com
102 PART I Nutrition Assessment
Analytes Reference Range* Significance
Red blood cells 4.7-6.1 3 106/ml (males); 4.7-6.1 1012/L
4.2-5.4 3 106/ml (females); 4.2-5.4 1012/L In addition to nutritional deficits, may be decreased in those with hemorrhage, hemolysis, genetic aberrations, marrow failure, or renal disease or who are taking certain drugs; not sensitive for iron, vitamin B12, or folate deficiencies
Hemoglobin concentration
14-18 g/dl; 8.7-11.2 mmol/L (males) 12-16 g/dl; 7.4-9.9 mmol/L (females) .11 g/dl; .6.8 mmol/L (pregnant females) 14-24 g/dl; 8.7-14.9 mmol/L (newborns)
In addition to nutritional deficits, may be decreased in those with hemorrhage, hemolysis, genetic aberrations, marrow failure, or renal disease or who are taking certain drugs
Hematocrit 42%-52% (males) 35%-47% (females) 33% (pregnant females) 44%-64% (newborns)
In addition to nutritional deficits, may be decreased in those with hemorrhage, hemolysis, genetic aberrations, marrow failure, or renal disease or who are taking certain drugs
Somewhat affected by hydration status
MCV 80-99 fl
96-108 fl (newborns)
Decreased (microcytic) in presence of iron deficiency, thalassemia trait and chronic renal failure; normal or decreased in anemia of chronic disease; increased (macro- cytic) in presence of vitamin B12 or folate deficiency and genetic defects in DNA synthesis; neither microcytosis nor macrocytosis sensitive to marginal nutrient deficiencies
MCH 27-31 pg/cell
23-34 pg (newborns) Causes of abnormal values similar to those for MCV
MCHC 32-36 g/dl; 32-36%
32-33 g/dl; 32-33% (newborns) Decreased in those with iron deficiency and thalassemia trait; not sensitive to mar- ginal nutrient deficiencies
WBC 5-10 3 109/L; 5,000-10,000/mm3 (2 yr-adult) 6-17 3 109/L; 6,000-17,000/mm3 (,2 yr) 9-30 3 109; 9,000-30,000/mm3 (newborns)
Increased (leukocytosis) in those with infection, neoplasia; stress decreased (leuco- penia) in those with malnutrition, autoimmune diseases, or overwhelming infec- tions or who are receiving chemotherapy or radiation therapy
Differential 55%-70% neutrophils 20-40% lymphocytes 2-8% monocytes 1%-4% eosinophils 0.5%-1% basophils
Neutrophilia: Ketoacidosis, trauma, stress, pus-forming infections, leukemia Neutropenia: malnutrition, aplastic anemia, chemotherapy, overwhelming
infection
Lymphocytosis: Infection, leukemia, myeloma, mononucleosis Lymphocytopenia: Leukemia, chemotherapy, sepsis, AIDS
Eosinophilia: Parasitic infestation, allergy, eczema, leukemia, autoimmune disease Eosinopenia: Increased steroid production
Basophilia: Leukemia Basopenia: Allergy
Analyte Expected Value Significance Specific
gravity 1.010-1.025 Can be used to test and monitor the concentrating and diluting abilities of the kidney and hydration status; low in those with diabetes insipidus, glomerulonephritis, or pyelonephritis; high in those with vomiting, diarrhea, sweating, fever, adrenal insufficiency, hepatic diseases, or heart failure pH 4.6-8 (normal diet) Acidic in those with a high-protein diet or acidosis (e.g., uncontrolled DM or starvation), during
administration of some drugs, and in association with uric acid, cystine, and calcium oxalate kidney stones; alkaline in individuals consuming diets rich in vegetables or dairy products and in those with a urinary tract infection, immediately after meals, with some drugs, and in those with phosphate and calcium carbonate kidney stones
Protein 2-8 mg/dl Marked proteinuria in those with nephrotic syndrome, severe glomerulonephritis, or congestive heart failure; moderate in those with most renal diseases, preeclampsia, or urinary tract inflamma- tion; minimal in those with certain renal diseases or lower urinary tract disorders
Glucose Not detected (2-10 g/dl
in DM) Positive in those with DM; rarely in benign conditions
Ketones Negative Positive in those with uncontrolled DM (usually type 1); also positive in those with a fever, anorexia, certain GI disturbances, persistent vomiting, or cachexia or who are fasting or starving
Blood Negative Indicates urinary tract infection, neoplasm, or trauma; also positive in those with traumatic muscle injuries or hemolytic anemia
Bilirubin Not detected Index of unconjugated bilirubin; increase in those with certain liver diseases (e.g., gallstones) Urobilinogen 0.1-1 units/dl Index of conjugated bilirubin; increased in those with hemolytic conditions; used to distinguish
among hepatic diseases
Nitrite Negative Index of bacteriuria
Leukocyte
esterase Negative Indirect test of bacteriuria; detects leukocytes
TABLE 7-2 Constituents of the Hemogram: Complete Blood Count and Differential
TABLE 7-3 Chemical Tests in a Urinalysis
AIDS, Acquired immune deficiency syndrome; DNA, deoxyribonucleic acid; MCH, mean corpuscular hemoglobin; MCHC, mean corpuscular hemoglobin concentration; MCV, mean corpuscular volume.
*Reference ranges may vary slightly among laboratories.
DM, Diabetes mellitus; GI, gastrointestinal.