Lab

Free PSA

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Free PSA, Free Prostate Specific Antigen

  • Mechanism
  1. Free PSA increases more in Benign Prostatic Hypertrophy
  2. PSA associated with cancer is more protein bound
  • Indication
  1. Detection of Prostate Cancer when PSA 2.5 to 10 ng/ml
  • Efficacy
  1. Improved Specificity when combined with PSA
  • Interpretation
  1. Free PSA >27% with lower likelihood of Prostate Cancer
  2. Values suggestive of Prostate Cancer
    1. Total PSA 3.0 to 4.0 with Free PSA <19%
    2. Total PSA 4.0 to 10.0 with Free PSA <17 to 24%