Prostate

[henry1938]

just wondering how accurate is a blood test for prostate
which would be the best option
ta

[gingejbee]

The PSA test isn't that "accurate"...but it does give a reasonable result- indicating if further investigation may be required.

[Sqad]

One blood test for prostate cancer (PSA)shows that 70-80% of men with a raised PSA do NOT have cancer.

The advantage of the PSA is that if subsequent tests show a rising PSA then this may well be significant.

Biopsy is the most reliable.

[Bazile]

It's not a test for a definitive diagnosis .

Rather , it's an indication / marker that you may have a prostate issue ( if the reading is above a certain figure ) ; which may warrant further investigation

[bhg481]

Worth reading this henry:

http://www.nhs.uk/Livewell/Prostatehealth/Pages/psa-test.aspx

[Sqad]

P.S 20% of men who DO have cancer have a normal PSA.

[Clanad]

Here in the U.S., my Doc relies on this testing but also compares it to the standard PSA testing.

"Some doctors might consider using newer types of PSA tests (discussed below) to help decide if you need a prostate biopsy, but not all doctors agree on how to use these other PSA tests. If your PSA test result isn’t normal, ask your doctor to discuss your cancer risk and your need for further tests.

Percent-free PSA

PSA occurs in 2 major forms in the blood. One form is attached to blood proteins, while the other circulates free (unattached). The percent-free PSA (fPSA) is the ratio of how much PSA circulates free compared to the total PSA level. The percentage of free PSA is lower in men who have prostate cancer than in men who do not.

This test is sometimes used to help decide if you should have a prostate biopsy if your PSA results are in the borderline range (like between 4 and 10). A lower percent-free PSA means that your likelihood of having prostate cancer is higher and you should probably have a biopsy. Many doctors recommend biopsies for men whose percent-free PSA is 10% or less, and advise that men consider a biopsy if it is between 10% and 25%. Using these cutoffs detects most cancers and helps some men avoid unnecessary prostate biopsies. This test is widely used, but not all doctors agree that 25% is the best cutoff point to decide on a biopsy, and the cutoff may change depending on the overall PSA level.

A newer test, known as complexed PSA, directly measures the amount of PSA that is attached to other proteins (the portion of PSA that is not “free”). This test is done instead of checking the total and free PSA, and it could give the same amount of information as the other tests done separately. Studies are now under way to see if this test provides the same level of accuracy."

[Peter Pedant]

my turn my turn - - -say test X measures disease X

the question you really want answered, is:
if test X is positive - what chance do I have of having disease X ?

this chance has a name ! PPV [ positive predictive value]

according to this
http://www.uptodate.com/contents/screening-for-prostate-cancer

is is one third or thirty per cent

that is if you have a PSA of greater than 4 then the chance you have prostate cancer is a third .....

God I didnt think it was that low ( or that bad ) that is that the test was that inefficient


By contrast for example the test for HIV ( HIV test ) predicts HIV in at least 99% ( if you test positive for HIV then you have HIV )