N ORMAL L AB V ALUES Paula Ruedebusch, ARNP, DNP

I MPORTANCE Electrolytes become ions Acquire capacity to conduct electricity Present in human body Balance is necessary for NORMAL function of cells and organs Can measure in blood (urine, sweat, etc) Hunt for etiology of disease

N ORMS FOR THIS COURSE Text pages except for K+ and HCO3- Many variations of “normal” Lab tests and ranges vary across testing centers Boards will be similar MUST MEMORIZE!!

B ASIC M ETABOLIC P ANEL Measures electrolytes, chemicals, metabolic end products & substrates Consists of Glucose, Blood Urea Nitrogen (BUN), Creatinine, Na +, K +, Cl -, Bicarbonate (HCO 3 - ), Ca 2+

S ODIUM (N A +) Measures serum sodium level ● Major cation in EC space ● Balance between dietary intake and renal excretion Normal: 136 – 145 mEq/L Critical: 160 mEq/L ↑ (hypernatremia): ↑ Na + intake, ↓ Na + loss, Excessive free body H 2 O loss ↓ (hyponatremia): ↓ Na + intake, ↑ Na + loss, ↑ free body H 2 O

P OTASSIUM (K+) Measures serum potassium level ● Major cation within cell Normal: 3.5 – 5.5 mEq/L Critical: 6.5 mEq/L ↑ (hyperkalemia): excessive intake, acidosis, acute/chronic renal failure, Addison disease, hypoaldosteronism, infection, dehydration ↓ (hypokalemia): deficient intake, burns, hyperaldosteronism, Cushing syndrome, licorice ingestion, alkalosis

C ALCIUM (C A ++) Measures serum calcium level ● Direct measurement ● Used to evaluate parathyroid function & Ca metabolism ● Used to monitor renal failure, renal transplantation, hyperparathyroidism, various malignancies, & Ca level when giving large-volume blood transfusions Normal: Total = 8.8 – 10.5 mg/dL Critical: Total 13 mg/dL ↑ (hypercalcemia): hyperparathyroidism, bone mets, prolonged immobilization, vit D intoxication, hyperthyroidism ↓ (hypocalcemia): hypoparathyroidism, renal failure, rickets, vit D deficiency, osteomalacia, pancreatitis, alkalosis, malabsorption, fat embolism

M AGNESIUM (M G ++) Measures magnesium content of blood ● Affects oxygen uptake ● Energy production ● Electrolyte balance ● Intestinal absorption, renal excrection Normal: mg/dL ↑: hemolysis, renal insufficiency, DKA, adrenal insufficiency, hyperparathyroidism, lithium intoxication ↓: DMII, alcoholism, loop diuretics, antibiotics that block resorption in loop of henle

C HLORIDE (C L -) Measures serum chloride level ● Major anion in EC space ● Helps maintain electrical neutrality; follows sodium Normal: 95 – 105 mEq/L Critical: 115 mEq/L ↑ (hyperchloremia): dehydration, metabolic acidosis, Cushing syndrome, renal dysfunction, respiratory alkalosis, hyperparathyroidism ↓ (hypochloremia): overhydration, SIADH, CHF, chronic respiratory acidosis, metabolic alkalosis, Addison’s disease, Aldosteronism, vomiting/prolonged gastric suction, hypokalemia

B ICARBONATE (HCO3-) Measures CO 2 content of blood ● Major role in acid-base balance ● Regulated by kidneys ● Used to evaluate pt pH status & electrolytes Normal: 22 – 26 mEq/L Critical: < 6 mEq/L ↑: severe vomiting, high-volume gastric suction, aldosteronism, mercurial diuretic use, COPD, metabolic alkalosis ↓: chronic diarrhea, chronic loop diuretic use, renal failure, DKA, starvation, metabolic acidosis, shock

P HOSPHATE 2.5 – 5.0 mg/dL Abnormal in bone, parathyroid and renal disease

G LUCOSE Direct measure of blood glucose ● Commonly used to evaluate diabetic pts ● Part of “routine” testing Normal: mg/dL Critical: 400 mg/dL ↑ (hyperglycemia): DM, acute stress response, Cushing syndrome, pheochromocytoma, chronic renal failure, acute pancreatitis, acromegaly, corticosteroid therapy ↓ (hypoglycemia): insulinoma, hypothyroidism, hypopituitarism, Addison’s disease, extensive liver disease, insulin overdose, starvation

BUN Measures urea nitrogen in blood ● End product of protein metabolism (produced in liver) ● Indirect measure of renal function & glomerular function (excretion) ● Measure of liver metabolic function ● Part of routine labs ● Usually interpreted along with Cr (less accurate than Cr for renal disease) Normal: mg/dL ↑: prerenal causes, renal causes, postrenal azotemia ↓: liver failure, overhydration because of SIADH, neg nitrogen balance, pregnancy, nephrotic syndrome

C REATININE Measures serum creatinine ● Catabolic product of creatine phosphate (skeletal muscle contraction) ● Excreted entirely by kidneys → direct measure of renal function ● Minimally affected by liver function ● Elevation occurs slower than BUN ● Doubling ≈ 50% reduction in GFR Normal: 0.6 – 1.2 mg/dL Critical: > 4 mg/dL ↑: diseases affecting renal function (glomerulonephritis, pyelonephritis, ATN, urinary tract obstruction, reduced renal blood flow, diabetic nephropathy, nephritis), rhabdomyolysis, acromegaly, gigantism ↓: decreased muscle mass

BUN & C REATININE VS. RENAL FUNCTION BUN and Creatinine ↑ = Kidney Function ↓ BUN and Creatinine ↓ = Kidney Function ↑ If kidneys are not working well, they are not clearing BUN and Creatinine, so the values go ↑ ↑ ↑

C OMPREHENSIVE M ETABOLIC P ANEL (CMP) Includes all components of BMP plus Albumin, Total protein, Alkaline phosphatase (ALP), Alanine aminotransferase (ALT), Aspartate aminotransferase (AST) and Bilirubin

R ELEVANCE Patient improvement! ☺ Patient worsening! ☹ Is therapy effective? Therapy/treatment recommendations? Objective signs of invisible changes Nursing care plan initiation Changes to nursing care plan Criteria for discharge

R ECAP ! Na+ = mEq/L K+ = mEq/L Ca++ = mg/dL Mg++ = mg/dL Cl- = mEq/L HCO3- = mEq/L Phosphate = mg/dL Glucose (fasting) = mg/dL BUN = 7-18 mg/dL Creatinine = mg/dL

Important to remember! Additional items on CMP: Albumin, total protein, ALP, ALT, AST MEMORIZE the values Get comfortable recognizing abnormals Practice, practice, practice!