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UNIT 4 Supporting Physiological Functioning
DIAGNOSTIC TESTING
Tests for Assessing Wounds Test
Normal Range
Comments
Leukocyte (WBC) count
Usually done as a part of a complete blood count (CBC) but may be ordered as an independent test.White blood cells (WBCs) may increase when a wound develops; continued elevation may signal infection.A low WBC count may delay wound healing. Leukocytes are responsible for an inflammatory reaction at the wound site, phagocytosis of bacteria and cellular debris, and the creation of antibodies. Low serum levels indicate limited nutritional stores that delay wound healing or place the patient at high risk for pressure injury. Serum protein may be monitored as an indicator of the ability to heal a wound or prevent a pressure injury. Serum protein and albumin levels are closely related. However, both fluctuate slowly.A more accurate measure of a patient’s immediate protein stores is reflected in the prealbumin level. In the presence of an inflammatory and necrotic process, blood proteins are altered.This test indicates whether the RBCs stick together, become heavier, and settle at the bottom of a laboratory tube when held vertically. Prolonged coagulation times may result in excessive blood loss or ongoing bleeding in the wound bed. Shortened coagulation times increase the risk for blood clot formation problems, such as deep vein thrombosis, pulmonary embolus, or stroke. Altered coagulation may result from anticoagulant medications, a concurrent illness, trauma, or reaction to transfusions.
5,000–10,000/mm 3
Serum protein
6.0–8.0 g/dL
Serum albumin
3.4–4.8 g/dL
Serum prealbumin
12–42 mg/dL
Erythrocyte sedimentation rate (ESR)
<50 years old: 0–15 mm/hr; >50 years old: 0–20 mm/hr
Coagulation studies: Partial thromboplastin time, activated (aPTT)
Varies with respect to equipment and reagents used. Critical values: >70 seconds or <53 seconds
Prothrombin time (clotting time)
Critical values: >20 seconds (uncoagulated) or 3 times normal control (anticoagulated) <2.0 for patients not receiving anticoagulation therapy; 2.0–3.0 for those receiving coagulation therapy
International normalized ratio (INR)
A standardized test to evaluate clotting times, considered the gold standard.
Wound cultures
Negative; no growth of pathogens Wound cultures may be prescribed to determine the types of bacteria present in the wound. Cultures may be obtained by swab, aspiration, or tissue biopsy.A positive culture may not indicate an infection as chronic wounds are colonized with bacteria. Negative; no growth of pathogens Wounds are not considered infected unless the bacteria count exceeds 100,000 organisms per gram of tissue. Exception: The presence of beta-hemolytic streptococci in any number indicates infection.
Tissue biopsy
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