Lab Values

Patients in the ICU are generally critically ill and will have many different labs drawn and tests completed. It is important to know the normal values and what to look for in the chart. But understand that each situation is case-specific. You may be able to work with the patient outside the standardized range/cutoff. Knowledge of the effects of labs on the patient’s affect and/or ability to participate is important and will help guide clinical thinking. Included are a few common lab values and considerations.

  • Purpose: Measure’s the blood’s ability to carry oxygen

    Normal Range: Males: 13-18 g/dl; Females: 12-16 g/dl

    Abnormal Value: <7 g/dl which can indicate the extent of anemia or polycythemia.

    • Causes can include: renal failure, cirrhosis, burns, hyperthyroidism, or certain systemic diseases

    Clinical Consideration: low hemoglobin indicates that the heart is working harder to oxygenate the body. Consider therapy in bed only. Look at the trend and norms for the particular patient and/or diagnosis. Are there plans for a blood transfusion? Engage in a clinical discussion with the nurse and/or MD as needed.

  • Purpose: measures the percent of red blood cells in the total blood volume. Helpful in diagnosing abnormal hydration levels, anemia, and polycythemia.

    Normal Range: Males: 37-49%; Females: 36-46%

    Abnormal Value: < 24%

    Clinical Consideration: Patients may exhibit weakness, increased fatigue, tachycardia, decreased exercise/activity tolerance, dyspnea on exertion, and heart palpitations. Consider therapy in bed only. Look at the trend and norms for the particular patient and/or diagnosis. Engage in a clinical discussion with the nurse and/or MD as needed.

  • Partial Pressure of Oxygen (PaO2)

    Purpose: Pressure of O2 dissolved in arterial blood. Used to monitor pulmonary status and determine how well O2 can move from the lungs into the blood. Measuring PaO2 is the most accurate test for blood oxygen level.

    Normal Range: 80-95 mm Hg

    • For reference an oxygen saturation of 90% is equal to PaO2 of 60 mm Hg

    Abnormal Value: <80 mm Hg (hypoxemia)

    Clinical Consideration:

    • Signs of hypoxemia can include: mental status changes, tachycardia, and lightheadedness. Be sure to monitor vitals, treat activity intolerance, and instruct in breathing exercises as needed.

    • Be sure to monitor vitals and treat to tolerance.

  • Purpose: the standardized number of when the blood is sufficiently anticoagulated for the patient’s specific condition and considered to be at a therapeutic level

    Normal Range: 0.9-1.1

    • Therapeutic INR will vary based on the diagnosis. You may see a range of 2-3 for patients anticoagulated for a-fib, coronary artery disease, cerebrovascular disease, DVT, or patients following MI

    Abnormal Value: 3.5-5 or >5

    Clinical Consideration:

    • 3.5-5: Look at trends and norms for the particular patient and/or diagnosis. Is the patient anticoagulated? Do they have a mechanical heart valve?

    • >5: There is an increased risk for bleeding. Consider therapy in bed only. Look at trends and norms for the particular patient and/or diagnosis. Is the patient anticoagulated? Do they have a mechanical heart valve? Engage in a clinical discussion with the nurse and/or MD as needed.

  • Purpose: important for neuromuscular function, action potentials, and cardiac muscle contraction and conductivity. Potassium value provides information on renal and adrenal systems as well as acid-base imbalances.

    Normal Range: 3.5-5.0 mEq/l

    Abnormal Value: <3.2 (hypokalemia) or > 5.2 mEq/l (hyperkalemia)

    Clinical Consideration: Look at trends and norms for the particular patient and/or diagnosis. Look at changes in the EKG.

    • Symptoms of hyperkalemia can include: abdominal cramping, nausea, diarrhea, muscle weakness, flaccid paralysis, paresthesias, fatigue, irritability, CKG changes, or cardiac arrest

    • Symptoms of hypokalemia can include: paralytic ileum, decreased peristalsis, abdominal dissension, constipation, muscle weakness, fatigue, leg cramps, paresthesias, disorientation, hypotension, dysrhythmias, or cardiac or respiratory arrest.

  • Purpose: is a determinant of fluid volume in the body. Helps to facilitate nerve conduction, neuromuscular function, and glandular secretion.

    Normal Range: 135-145 mEq/l

    Abnormal Value: <130 (hyponatremia) or > 150 mEq/l (hypernatremia)

    Clinical Consideration: Note any fluid restrictions. Look for any trends and changes in EKG. Also assess for any mental status changes.

    • Symptoms of hypernatremia can include: change in mental status, confusion, ataxia, convulsions, hypertension, tachycardia, pulmonary edema, dyspnea, and respiratory arrest.

    • Symptoms of hyponatremia can include: nausea, vomiting, abdominal cramps, muscle twitching, weakness, lethargy, confusion, hypotension, tachycardia, and seizures.

References

Evangelist, M., & Gartenberg, A. (2016, February 8). Toolkit for developing an occupational therapy program in the ICU. SIS Quarterly Practice Connections, 1(1), 20–22.

Evangelist, M., & Gartenberg, A. (2017). Vitals: A systemic approach to ICU chart review. In H. Smith-Gabai & S. E. Holm (Eds.), Occupational Therapy in Acute Care (2nd ed., pp. 130–131). AOTA Press.

Matthies, M. J., & Smith-Gabai, H. (2017). Laboratory Values. In H. Smith-Gabai & S. E. Holm (Eds.), Occupational Therapy in Acute Care (2nd ed., pp. 149–174). AOTA Press.

Smith-Gabai, H. (2011). Laboratory Values. In H. Smith-Gabai (Ed.), Occupational Therapy in Acute Care (1st ed., pp. 713–738). AOTA Press.