TOTAL/FREE PSA RATIO

שלום רב, קיבלתי תוצאות בדיקת psa עם הנתון: "Free/Total PSA Ratio" מה זה אומר? מה זה ה RATIO? מה זה ומה ההבדל בין FREE PSA לבין TOTAL PSA? מה התוצאה שאמורה להדליק נורה אדומה? האם תוצאה של: total psa - 8.04 free psa - 1.10 free/total psa ratio - 13.7 היא נורמלית? בתודה רבה

אני מתבסס על http://www.mdsdx.com/MDS_Diagnostic_Services/Patients/TestInfo/Special/prostate.asp שקובע ש: August 18, 2004 -------------------------------------------------------------------------------- PSA Ratio - Physician Overview Prostatic-specific antigen (PSA) has been accepted as a useful blood test to aid in the detection AND clinical management of prostate cancer, particularly when used in conjunction with rectal examination. Elevated (> 20.0 µg/L) concentrations of serum PSA have been documented in patients with advanced prostatic cancer, however, accurate interpretation of PSA values between 4.0-10.0 µg/L is difficult. Moderately increased concentrations of PSA may occur in patients with benign prostatic hyperplasia (BPH) AND inflammatory prostatic diseases. To differentiate between prostatic cancer AND BPH, patients with elevated serum PSAs are followed-up with more complicated, invasive AND expensive procedures, including prostatic biopsy. A new blood test, "PSA Ratio," has been suggested as a more specific diagnostic tool to reduce the number of biopsies required for differential diagnosis of prostatic cancer. What is Free PSA AND why is it important? In human serum, PSA exists in two forms: PSA complexed to proteins, primarily 1-antichymotrypsin (ACT) AND -macroglobulin; AND noncomplexed OR "free" PSA. Historically, total PSA concentration (the sum of PSA bound to ACT AND free-PSA), has been measured AND reported. Research has demonstrated that patients with prostatic cancer have lower levels of free-PSA (f-PSA) than patients with BPH. Furthermore, the ratio of free/total PSA (f/t) is significantly lower in patients with prostatic cancer AND this may improve the clinical specificity of PSA. Data from various studies suggest that between 20-60% of negative biopsies could be avoided through the measurement of PSA ratios. When should PSA Ratio be ordered? The f/t PSA ratio is most useful clinically, in cases where total PSA concentration is in the range of 4.0-10.0 µg/L. The f/t PSA ratio will not significantly improve clinical specificity of diagnosis when the total PSA concentrations is <4.0 µg/L. False negative f/t ratios may occur in 10% of prostatic cancer patients. NOTE: For maximum clinical predictive value the f/t PSA ratio should be interpreted together with total PSA values AND clinical findings including a rectal examination. How to order PSA Ratio A request for i) free PSA OR ii) free PSA AND total PSA OR iii) PSA ratio, will result in measurement of free PSA, total PSA AND calculation of the f/t PSA ratio. A request for PSA OR total PSA as an individual test will provide a report for the total PSA only. PSA Ratio AND total PSA may not be insured by your provincial health plan but it may be covered by a patient's insurance plan. Specimens Requirements Collect 5 mls of blood in an SST vacutainer tube. (Note: sample must be collected prior to rectal examination). The sample must be centrifuged within 30 minutes of collection AND a serum aliquot separated within 2 hours of collection. Serum specimens should be transported AND stored frozen. Interpretation of Results f/t PSA Ratio Probability of Prostatic Cancer f/t PSA Ratio -------------------------------------------------------------------------------- Probability of Prostatic Cancer -------------------------------------------------------------------------------- <0.10 >0.31 High Low זה בשבר עשרוני באחוזים זה 10 אחוז ו 31 אחוז בהתאמה. הכתבה אומרת שבתחום בין 4 לבין 10 המשך הטיפול אינו חד משמעי. מעל 10 יש לבצע ביאופסיה כדי לשלול ממאירות ומתחת 4 צריך להמשיך לבדוק כל שנה או חצי שנה (תלוי בשאר הממצאים). בתחום בין 4 ל 10 היחס האמור עוזר להחליט אם לבצע ביאופסיה. במקרה שלך התוצאה מלמדת שצריך לבצע את הביאופסיה כדי לשלול ממאירות.

לדני שלום רב ה- PSA מופיע בדם בשתי צורות : PSA "רגיל" ו-PSA שמסתובב חופשי בדם. היחס ביניהם יכול לתת מדד נוסף לגבי הצורך בביוצוע ביופסיה של הערמונית . ככל שהיחס יותר נמוך זה פחות טוב. אם ה- PSA 8.0 והיחס 13.7 לפי דעתי זה מחייב ביופסיה של הערמונית . ד"ר אריאלי