Navigation Links
PSA TestingHow Much is Too Much?


For more than 20 years, the PSA test has been widely used as the gold standard for prostate cancer screening. In one of the most dramatic reversals in recent diagnostic science, a recent study at Stanford University School of Medicine and findings by other researchers have now put the utility of the procedure in grave doubt.

Indeed, The PSA era is over in the United States, said Thomas Stamey, MD, professor of urology and lead author of the study published in the October 2004 issue of the Journal of Urology. Our study raises a very serious question of whether a man should even use the PSA test for prostate cancer screening any more, Stamey said. The researchers opinion carries great influence, since it was Stameys work in the late 80s that propelled PSA testing into widespread use (and prompted the corresponding practice of routinely removing prostates in response to high PSA levels).

As time has passed, however, Stamey has concluded that PSA testing is unable to predict the extent or severity of prostate cancer but, instead, provides a measure of benign prostatic hyperplasia.

Mark Twain once famously quipped that, The report of my death was an exaggeration. The death knell of PSA may also have sounded too soon, since the assay is likely to continue to provide useful data, albeit in far less universal applications. Stamey and his colleagues identified two important and continuing uses for PSA testing in their recent paper. They noted that PSA levels quite accurately correlate with prostate size and that the test thus serves as a direct measure of benign prostatic hyperplasia. Stamey noted that the assay is also helpful for monitoring patients following prostate removal because it can indicate residual prostate cancer that has metastasized.

As with many disease screens, PSA tests now range from assay reagents used in multi-function clinical laboratory analyzer systems to rapidly performed, self-contained kits suitable for point of care use, to mail-in specimen collection kits available for clinical or home screenings.

Bio-Quant, Inc., San Diego, Calif., manufactures the OneStep PSA InstaTest designed to detect PSA concentration in whole blood or serum in concentrations as low as four ng/ml within 15 minutes. The result is read visually by observing symbols that develop during the test in a result window. The company says that comparative studies have demonstrated that relative sensitivity of InstaTest PSA is 100 percent, and its relative specificity is 98.5 percent.

Beckman Coulter, Inc., Fullerton, Calif., produces the Hybritech PSA Test and, as a confirmatory follow-up, the Hybritech free PSA Test. The Hybritech PSA test was the first assay approved by FDA for the detection of prostate cancer when used in combination with digital rectal examination (DRE) in men aged 50 years or older. The assay provides equimolar PSA measurement based on a monoclonal antibody pair. The company lists analytical sensitivity at <0.008 ng/mL ; measurement range to 150 ng/mL and precision at < 5% CV across the assay range. Time to first result is 20 minutes, using a serum sample of 25 L.

In the early 1990s, it was demonstrated that measuring the ratio of free to total PSA could further help in distinguishing prostate cancer from benign prostate disease. The Hybritech free PSA testalso the first test of its kind to receive approvalhelps determine the percent of free PSA and thereby improve the accuracy of prostate cancer detection while eliminating a projected 20 percent of all prostate biopsies . The free PSA test is used following a non-suspicious DRE and a total PSA test that shows moderately elevated PSA levels (between four and 10 ng/mL) in men aged 50 years and older.

Analytical sensitivity for this assay at <0.005 ng/mL ; measurement range to 20 ng/mL and precision at UniMed LLC, Natick, Mass., manufactures a Prostate Specific Antigen (PSA); Prostate Cancer Test collection kit that includes a fingertip blood sample stylet, specimen card. The user sends the prepaid mailer to the companys laboratory where it is analyzed using the Tandem PSA method for total PSA. The results are returned by mail.

Craig Medical Distribution, Inc., Vista, Calif., produces another FDA-approved sample collection kit: the PSA4 Screening Test, a quantitative assay for a whole blood sample. As with the UniMed product, a fingertip blood sample is enclosed in a pre-addressed, postage paid mailer and sent to the laboratory where the sample is tested, the results are tabulated in report form, reviewed by a physician and returned within five days.

Given the widespread prevalence of prostate cancer the search for markers more accurate than PSA are now being widely sought. Prior to their availability, PSA testing, while in a far more limited role, will continue to perform useful work.
'"/>




Related medicine technology :

1. Novel Human Tissue Transgenic Cancer Model May Offer Significant Advance Toward Accurately Modeling Human Cancer
2. HepaLifes PBS-1 Cells for Influenza Vaccine Production Prove Superior at International Conference
3. New Flu Vaccine from PepTcell Could Provide Immunity Against All Strains of Influenza Virus
4. BioCryst Presents Phase I Peramivir Data at the Options for the Control of Influenza Conference
5. New Flu Vaccine From PepTcell Could Provide Immunity Against All Strains of Influenza Virus
6. Hemispherx Presents Evidence of Ampligen Synergies with Existing Antivirals at International Avian Influenza Conference
7. Hemispherx Presents Potential Avian Influenza Treatment Breakthrough at Paris Conference
8. HepaLife Announces Scientific Presentation of PBS-1 Cell Line at International Influenza Meeting
9. Iomai to Announce Results From Phase 1 Influenza Trial and Host Webcast Tomorrow
10. VGX Pharmaceuticals Novel HIV and Pandemic Influenza DNA Vaccine Candidates Trigger Robust Immune Responses and Protection in Pre-Clinical Models
11. Data Show FluMist May Reduce Seasonal Influenza Burden Among Children in School, Daycare Settings

Post Your Comments:
*Name:
*Comment:
*Email:
(Date:6/24/2016)... June 24, 2016   Pulmatrix, Inc ., (NASDAQ: ... innovative inhaled drugs, announced today that it was added ... reconstituted its comprehensive set of U.S. and global ... is an important milestone for Pulmatrix," said Chief Executive ... awareness of our progress in developing drugs for crucial ...
(Date:6/23/2016)... -- Any dentist who has made an implant supported denture ... of them do not even offer this as a viable ... costs involved. And those who ARE able to offer that ... cost that the majority of today,s patients would not be ... , founder of Dental Evolutions Inc. and inventor of Implanova ...
(Date:6/23/2016)... , June 23, 2016 ... CAPR ), a biotechnology company focused on ... today announced that patient enrollment in its ongoing ... Duchenne) has exceeded 50% of its 24-patient target. ... in the third quarter of 2016, and to ...
Breaking Medicine Technology:
(Date:6/26/2016)... ... ... Pixel Film Studios Released ProSlice Levels, a Media Slicing Effect Plugin ... whole new perspective by using the title layers in ProSlice Levels to split-up ... Levels contains over 30 Different presets to choose from. FCPX users can ...
(Date:6/25/2016)... Austin, TX (PRWEB) , ... June 25, 2016 , ... ... Fellow of the American College of Mohs Surgery and to Dr. Russell Peckham for ... popular and highly effective treatment for skin cancer. The selective fellowship in Mohs Micrographic ...
(Date:6/25/2016)... (PRWEB) , ... June 25, 2016 , ... ... athletes and non-athletes recover from injury. Recently, he has implemented orthobiologic procedures as ... City area —Johnson is one of the first doctors to perform the treatment. ...
(Date:6/24/2016)... (PRWEB) , ... June 24, 2016 , ... June 19, ... the dangers associated with chronic pain and the benefits of holistic treatments, Serenity ... who are suffering with Sickle Cell Disease. , Sickle Cell Disease (SCD) is a ...
(Date:6/24/2016)... Diego, CA (PRWEB) , ... June 24, 2016 , ... ... with the American Cancer Society and the Road To Recovery® program to drive cancer ... to seniors and other adults to ensure the highest quality of life and ongoing ...
Breaking Medicine News(10 mins):