Lab Values

CBC: Complete Blood Count

Normal Rehab Considerations
RBC Male: 4.7-6.1×10^6/uL,Female: 4.2-5.4×10^6/uL N/A (In cases of acute anemia use Hgb and HcT)
HgB Male: 14-17Gm/dL,Female: 12-16Gm/dL  < 8gm/dL: essential daily activities only, hold physical therapy
HCT Male: 43-49%,Female: 38-44% < 25%: essential daily activities only, hold physical therapy
WBC 4,500-10,000×10^6/uL <5,000 with fever hold PT**
Platelets 150-350,00×10^6/uL < 10,000 and /or temperature > 100.5 degrees

**No current accepted guidelines exist for upper limit cut off scores. However post operatively patients may demonstrate increases up of 3,000uL during the first 2 days due to the systemic response to imposed trauma (surgery)(2,3). In general it is difficult to detect infection before day 7 because, especially with WBC alone(2,3). Use clinical presentation to determine presence of infection.



Normal Rehab Considerations
Sodium (Na+) 135-145mEq/L
  • Reductions: Cramps, weakness, confusion
  • Elevations: Fluid retention, swelling, hypertension
Potassium (K+) 3.5-5.0mEg/L
  • Reductions: Flattened Twaves, arrhythmias, muscle weakness
  • Elevations: Peaked Twaves, shortened Q-Twave interval
Calcium (Ca2+)  8.5-10.5 mg/dl
  • Reductions (Moderate to severe): parathesias, muscle spasms and seizure and QT interval prolongations
  • Elevations (severe only): bradycardia, AV block, and short QT interval, coma
Magnesium (Mg2+) 1.7 to 2.2 mg/dl
  • Reductions: prolonged PR or QT intervals, T-wave flattening or inversion, SVT, Ventricular arrhythmias.
  • Elevations: weakness, respiratory failure, coma, paralysis, respiratory failure
Chloride (Cl-)  95-105mEg/L
  • Elevations: Metabolic acidosis
  • Reductions: Often occur during metabolic alkalosis


  Normal Rehab Considerations
Prothombin time (PT) 11-12.5sec Assesses extrinsic pathway (fast system)

Therapeutic Range: 1-2 times normal

Risk of Bleeding:  > 2-3 times normal

International Normalized Ratio (INR) 0.9-1.1 Normalized Ratio of PT, used to assess effect of Warfarin (Coumadin)

Therapeutic Ranges:

  • Afib/DVT/PE: 2-3
  • Valve replacement: 2.5-3.5

Risk of Bleeding:

  • >4.0 light exercise only
  • >5.0 hold exercise, PT eval only
  • > 6.0 PT contraindicated
Activated Partial Thromboplastin time (aPTT)** 27–38 sec Used to assess the intrinsic pathway (slow system) and effect of heparin therapy.

Risk of Bleeding: >1-2 times normal

D-Dimer >500ug/L Used to rule in/out presence of DVT or PE and confirm presence of DIC

**Often patients are given heparin as a bridge to long term anti-coagulation therapy (ie, Warfarin) during that time aPTT is the lab value to monitor. Once a patient transitions to Warfarin, INR is then used to assess clotting risk.



Normal Rehab Considerations
Troponin <0.1-0.4 ng/ml Elevations detectable as early as 2 hrs after MI but not reliably elevated in all patients until 6 to 12 hrs.MUST RULE OUT OTHER CAUSES OF ELEVATION TO DIAGNOSE MI IF MI DIAGNOSED MUST WAIT FOR 2 CONSECUTIVE DOWNTRENDING VALUES BEFORE INITIATING PHYSICAL THERAPY***
CPK-MB/CK-MB 0-3 ng/ml Elevation within 4 to 8 hrs after coronary artery occlusion, peak between 12 and 24 hours
BNP 0.5-30 pg/mL Circulating peptide, indicates cardiac ventricular stretch/over-stretch

  • <100 pg/mL indicate no heart failure.
  • 100-300 pg/mL suggest heart failure is present. 
  • 300-600pg/mL suggest mild heart failure is present
  • >600pg/mL suggest moderate to severe heart failure is present

**Follow institutions policy, some may require 3 consecutive.



1) APTA Acute Care section, Lab values interpretation resources, Update 2013.

2) Takahashi J et al, Usefulness of White Blood Cell Differential for Early Diagnosis of Surgical Wound Infection Following Spinal Instrumentation Surgery, SPINE Volume 31, Number 9, pp 1020–1025.

3) Deirmengian G,  Leukocytosis Is Common After Total Hip and Knee Arthroplasty, Clin Orthop Relat Res (2011) 469:3031–3036



9 thoughts on “Lab Values

  1. I just discovered your blog. I want to thank you for your passion to provide this information. I was wondering if you could supply the citations for the indications/ contraindications for PT fir INR values?

  2. Can OTs follow these guidelines as well? Im an OTA student about to start fieldwork in an acute care setting and i’m trying to find a nice guideline chart for lab values and when to defer therapy.

  3. What about contraindications for manual therapy, including joint mobilizations and soft tissue work?

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