Prostate-Specific Antigen (PSA) Blood Test

Prostate-specific antigen (PSA) is a substance produced by the prostate gland. Elevated PSA levels may indicate prostate cancer or a noncancerous condition such as prostatitis or an enlarged prostate.

Most men have PSA levels under four (ng/mL) and this has traditionally been used as the cutoff for concern about risk of prostate cancer. Men with prostate cancer often have PSA levels higher than four, although cancer is a possibility at any PSA level. According to published reports, men who have a prostate gland that feels normal on examination and a PSA less than four have a 15% chance of having prostate cancer. Those with a PSA between four and 10 have a 25% chance of having prostate cancer and if the PSA is higher than 10, the risk increases to 67%.

In the past, most experts viewed PSA levels less than 4 ng/mL as normal. Due to the findings from more recent studies, some recommend lowering the cutoff levels that determine if a PSA value is normal or elevated. Some researchers encourage using less than 2.5 or 3 ng/mL as a cutoff for normal values, particularly in younger patients. Younger patients tend to have smaller prostates and lower PSA values, so any elevation of the PSA in younger men above 2.5 ng/mL is a cause for concern.

Just as important as the PSA number is the trend of that number (whether it is going up, how quickly, and over what period of time). It is important to understand that the PSA test is not perfect. Most men with elevated PSA levels have noncancerous prostate enlargement, which is a normal part of aging. Conversely, low levels of PSA in the bloodstream do not rule out the possibility of prostate cancer. However, most cases of early prostate cancer are found by a PSA blood test.

How Is The PSA Screening Test Done?

The test involves drawing blood, usually from the arm. The results are usually sent to a laboratory and most often come back within several days.

When Should I Have My PSA Levels Tested?

PSA blood tests and digital rectal exams should be done every year for men beginning at age 50, and earlier (age 40) for African American men and men with a family history of prostate cancer.

If your doctor is concerned that you might have prostate cancer based on either your PSA level or a rectal exam, a biopsy (a lab testing of a small amount of tissue from the prostate) will be this next step This is the only way to positively identify the presence of cancer.

What does the PSA test tell me about my prostate?

A raised PSA level can be a sign that you have prostate cancer. The PSA level is often raised well before any symptoms of prostate cancer develop. So the test can help to detect early prostate cancers (which may have a better chance of being successfully treated than more advanced prostate cancers.) As a rule, the higher the PSA level, the more likely that you have prostate cancer.

However, a raised PSA level can also occur in other prostate conditions such as some cases of benign enlargement of the prostate and inflammation of the prostate (prostatitis). In particular, a PSA level that is mildly or moderately raised has a good chance of being due to a benign condition, but could be due to prostate cancer. Overall, about 2 in 3 men with a raised PSA level do not have prostate cancer.

Also, if you do have prostate cancer, a single PSA test cannot tell you whether a prostate cancer is slow or fast growing.

And also, in some cases, the PSA level may be normal even when there is cancer there. Up to 1 in 5 men with prostate cancer have a normal PSA level.

So, the PSA test is not an accurate test for prostate cancer.

What conditions other than cancer cause the PSA level to rise?

The prostate typically enlarges as men grow older, and because small amounts of PSA are produced by the healthy prostate, its blood level tends to rise. Benign prostate enlargement (a condition which causes urinary symptoms such as poor flow, getting up at night), is a common non-cancer condition causing PSA levels to rise. For this reason, age-based thresholds, shown in Table 1, can be used to decide if a test result is abnormal. The percentage Free to Total PSA (described below) also gives an indication whether raised PSA is due to benign enlargement.

A temporary rise in the PSA can be caused by a number of conditions 1. Urinary infection, prostatitis (inflammation of the prostate), or a biopsy of the prostate can cause large rises while small rises can be caused by ejaculation and even bicycle riding. Because of these non-cancer causes of PSA rises, it is not surprising that if you have an abnormally high test result, it may not be due to prostate cancer. The chance that you have prostate cancer is only about one in three.

Table 1 - Suggested upper limits of PSA for different age groups 2

Age (years) Serum PSA (ng/ml)

40 - 49 2.0

50 - 59 3.0

60 - 69 4.0

70 - 79 5.5

Note: These levels are used only as a guide. It is possible to have prostate cancer and have a PSA level in the normal range, although this is uncommon.

If, in addition to the PSA test, you have a rectal examination, and it also is abnormal, your chances of having prostate cancer are higher, (one in two).

Other ways of measuring PSA have been developed in an effort to make the test more specific for prostate cancer. One of these is called the "Free to Total" PSA. This is a ratio, expressed as a percent. Much of the PSA in the blood is bound to protein, including that produced by cancer cells. But men with benign prostate enlargement have higher levels of free (unbound) PSA and so a higher Free to Total ratio. If the total PSA level is abnormal, the Free to Total PSA ratio will give an idea of whether the rise is due to benign disease or cancer. Cancer is more likely if the Free to Total percentage is below 10% 2. This test is available and widely used throughout Australia.

The Prostate specific antigen - PSA test

Serine protease is an enzyme that is produced in the prostate. The levels of this enzyme, which is commonly known as prostate specific antigen and abbreviated to PSA, can be used to gauge the likelihood that the patient has developed prostate cancer. The PSA test is generally taken in parallel with the digital rectal examination to ensure more accurate diagnosis.

Men normally have a low level of PSA in the blood stream; levels of PSA can become elevated if prostate function is disrupted. Elevated PSA levels alone are not necessary an indicator of cancer, as infections of the prostate and benign growths may also lead to leakage of PSA into the bloodstream. Other factors that increase the prostate specific antigen levels in a test include recent ejaculation and bike riding. In fact it has been recorded many times that patients with a high PSA score do not have cancerous growth of the prostate. The levels of PSA are also very dependent upon age and the size of the prostate, generally older people and larger prostates result in a naturally higher level of PSA’s. Conversely many drugs, such as those given to combat benign prostate hyperplasia can lead to a lowering of PSA levels and hence mask detection of cancerous growth.

what affects psa test?

We know that PSA mainly by the prostate gland has differentiated columnar epithelium secreting cells, prostate inflammation can destroy the prostate ductal and the original integrity of physical barriers,

Within the duct and acinar PSA leaking into the blood circulation, so that some of prostatitis patients showed increased serum PSA phenomenon.

Therefore, many scholars of the studies have shown that elevated serum PSA or PSAD in damage primarily to the degree of prostate tissue,

With the degree of inflammation within the prostate, and which is not directly related to,although the degree of prostate inflammation may be associated with prostate tissue injury.

We found that ? A type of serum PSA levels in patients with prostatitis was significantly higher than the normal control group.

With the increase in the number of EPS in the WBC, serum PSA level gradually increased,

But there is no significant difference, which may be due to fewer cases of this observation, but haven't been found the differences between the two.

The PSA level is related to the prostate volume, age, race, reagents, biopsy, and many other factors.

There is a wide range of different findings, some of which are mutually contradictory, and research is also related to differences in methods and patient selection.

However, now widely been recognized that not all patients with prostatitis had serum PSA levels appear higher.

Because prostatitis can increase serum PSA in the absence of any clinical symptoms, serum PSA levels were significantly higher in men, almost half have evidence of the existence of prostate tissue inflammation, which can cause clinical infection also increased serum PSA levels.

Therefore, elevated serum PSA levels of men, first of all a simple and convenient routine screening for the existence of prostatitis is needed, in particular, to see if whether there is no clinical symptoms of prostatitis.

After a clear diagnosis of prostatitis, you can provide an effective anti-infection treatment, allowing a gradual reduction of serum PSA levels, which can be extended to prostate biopsy,.

Repeated or not repeated prostate biopsy, or no need for biopsy. This will not only improve diagnosis of prostate cancer, prostate PSA and the degree of tissue injury has some relevance, The prostatic epithelial cells in the extent of damage and the degree of inflammatory cell infiltration, EPS microscopy in the number of WBC may reflect the extent of this infiltration, thus indirectly reflects the degree of glandular infringement.

Therefore, the number of WBC in EPS and serum PSA levels have a certain correlation, and confirmed by clinical practice.

And that's what affects psa test.

But it is not clear for the serum PSA levels and the relationship between the number of WBC in EPS, because these two effects is with the same type of receptor generated.