Lab Values & Implications for the PTA

Basic Metabolic Panel (BMP)

• Eight specific tests:
  • Electrolyte level
  • Acid–base balance
  • Blood sugar
  • Kidney status
• Tests: serum concentrations of sodium, potassium, chloride, calcium, BUN, creatinine, glucose, and carbon dioxide.
• Used as a screening tool, especially for diabetes and kidney disease.
• Sample obtained by venipuncture after 10–12 hours of fasting.
• Changes may indicate acute problems such as kidney failure, insulin shock, diabetic coma, and respiratory distress.

Sodium

• Critical determinant of fluid volume.
• Increased sodium leads to water retention; loss leads to water loss.
• Altered by excessive water intake/ADH or loss from sweating/decreased ADH.
• Impacts blood pressure and cell volume; neurons are vulnerable to swelling.

Potassium

• Important for excitable cells (nerve, muscles, heart).
• Arrhythmias and cardiac arrest can result from hypokalemia or hyperkalemia.
• Useful for information about renal and adrenal disorders and water and acid–base imbalances.
• Acts as part of the body's buffer system regulated by excretion through the urine.
• PTA Implications:
  • Potassium levels below $3.2 mEq/L$ or above $5.1 mEq/L$ may contraindicate physical therapy intervention.

Chloride and Bicarbonate

• Chloride levels change with sodium and water.
• Bicarbonate (HCO3 − ) is critical for acid–base balance.
• Low HCO3 − occurs in metabolic acidosis (e.g., DKA).
• Respiratory compensation: exhaling CO2 reduces HCO3 − .
• Renal system regulates pH by altering H+ in urine and synthesizing HCO3 − .

Magnesium

• Involved in regulation of excitable cells.
• Low magnesium causes arrhythmias, weakness, muscle spasms, and numbness.
• Reduced in diabetes, diuretic use, vomiting/diarrhea; increased by renal failure, hyperparathyroidism, or hypothyroidism.

Blood Glucose

• Measured to diagnose glucose homeostasis alterations.
• Tests: fasting blood sugar, 2-hour postprandial blood sugar (PPBS), oral glucose tolerance test, A1c test
• A1c test: reflects average blood glucose over weeks to months.
• PTA implications:
  • Ideal range: $80-120mg/dL$, but individual goals vary.
  • Monitor for hypoglycemia (less than $70mg/dL$) and hyperglycemia (over $120mg/dL$).
  • Exercise should occur after eating and not after insulin administration.

Blood Urea Nitrogen (BUN) and Creatinine

• Evaluate kidney function.
• Creatinine: waste product from muscle metabolism; elevated levels indicate declining kidney function.
• BUN: elevated by decreased renal blood flow, protein catabolism, or dietary protein intake; decreased in severe liver disease.
• PTA implications:
  • Changes in creatinine and BUN levels do not usually contraindicate physical or occupational therapy intervention.
  • Dehydration with elevated BUN could be a cause for light-headedness or dizziness during exercise.

Comprehensive and Hepatic Function Panels

• CMP: BMP + liver function tests (LFTs).
• LFTs: bilirubin, total protein, albumin, serum enzymes.
• Liver panel: assesses liver function, inflammation, and damage.
• Liver dysfunction increases risk of multiorgan dysfunction syndrome.
• ALT, AST, γ-glutamyl transferase, and lactate dehydrogenase (LDH), are elevated with injury to the hepatocytes.

Blood Ammonia

• Intermediate product of amino acid breakdown; severe liver injury can cause accumulation.
• Elevated ammonia can result in hepatic encephalopathy (confusion, lethargy, etc.).
• Combination of elevated ammonia and decreased glucose in a child is indicative of Reye's syndrome.
• PTA implications:
  • Elevation of liver enzymes indicates hepatic dysfunction.
  • Monitor for signs of hepatic disease.

Complete Blood Count (CBC)

• RBCs (erythrocytes), WBCs (leukocytes), and platelets are counted.
• RBC count (or Hgb/HCT) correlates with endurance and orthostatic tolerance.
• Anemia: relative decrease in blood's oxygen-carrying capacity.
• Ferritin: intracellular iron store; elevated levels increase risk for insulin-resistance syndrome.

White Blood Cells (WBCs)

• Increase suggests infection or inflammation.
• Decrease from bone marrow disease or chemotherapy.
• PTA implications:
  • Elevated WBC count (leukocytosis) indicates infection.
  • Low WBC count (leukopenia) increases infection risk.

Platelets

• Decreased by excessive bleeding, coagulation disorders, autoimmune disorders, or histocompatibility problems caused by transfusion of incompatible platelets.
• Decreased in bone marrow diseases, chronic bleeding, autoimmune disease, and factors that suppress cell production by the bone marrow (e.g., cancer, other chemotherapies) may be causes of a low platelet count (thrombocytopenia).

Red Blood Cell

• HCT is a simple test involving a small quantity of blood that can be obtained with a simple skin prick; Low HCT is indicative of anemia

Hemoglobin

• Hgb concentration usually provides the same information as HCT.

Mean Corpuscular Volume

• Different disease states may increase MCV, such as vitamin B12 or folic acid deficiency, or it may be decreased as in iron deficiency anemia or other causes of decreased cell volume.

Special Implications for the PTA: Blood Tests Complete Blood Count Hemoglobin and Hematocrit

• HCT and Hgb concentration may be decreased for a large number of reasons.
• Individuals with anemia may receive transfusions. Many facilities do not allow out-of-bed activity during transfusions, but others may allow careful lower level activity.

Platelets

• Platelets initiate the clotting sequence to plug damaged blood vessels.
• When the platelets are less than $15,000–20,000$ cells per $mm^3$, serious bleeding can occur and platelet transfusions may be required.