I found some interesting information on the National Cancer Institute Site on interpreting PSA test results.  It suggests you should talk to your doctor about the results, in particular, does the amount of the change in results from your last test to this one indicate a source of alarm, should the PSA test results be adjusted to take into account age.  I hope this info is helpful ... Here's an excerpt from the NCI document:<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" ?>

How are PSA test results reported?

PSA test results report the level of PSA detected in the blood. The test results are usually reported as nanograms of PSA per milliliter (ng/ml) of blood. In the past, most doctors considered PSA values below 4.0 ng/ml as normal. However, recent research found prostate cancer in men with PSA levels below 4.0 ng/ml (2). Many doctors are now using the following ranges, with some variation:

0 to 2.5 ng/ml is low

2.6 to 10 ng/ml is slightly to moderately elevated
10 to 19.9 ng/ml is moderately elevated
20 ng/ml or more is significantly elevated

There is no specific normal or abnormal PSA level. However, the higher a man’s PSA level, the more likely it is that cancer is present. But because various factors can cause PSA levels to fluctuate, one abnormal PSA test does not necessarily indicate a need for other diagnostic tests. When PSA levels continue to rise over time, other tests may be needed.

What if the test results show an elevated PSA level?

A man should discuss elevated PSA test results with his doctor. There are many possible reasons for an elevated PSA level, including prostate cancer, benign prostate enlargement, inflammation, infection, age, and race.

If no other symptoms suggest cancer, the doctor may recommend repeating DRE and PSA tests regularly to watch for any changes. If a man’s PSA levels have been increasing or if a suspicious lump is detected during the DRE, the doctor may recommend other tests to determine if there is cancer or another problem in the prostate. A urine test may be used to detect a urinary tract infection or blood in the urine. The doctor may recommend imaging tests, such as ultrasound (a test in which high-frequency sound waves are used to obtain images of the kidneys and bladder), x-rays, or cystoscopy (a procedure in which a doctor looks into the urethra and bladder through a thin, lighted tube). Medicine or surgery may be recommended if the problem is BPH or an infection.

If cancer is suspected, a biopsy is needed to determine if cancer is present in the prostate. During a biopsy, samples of prostate tissue are removed, usually with a needle, and viewed under a microscope. The doctor may use ultrasound to view the prostate during the biopsy, but ultrasound cannot be used alone to tell if cancer is present.

What are some of the limitations of the PSA test?

False positive tests: False positive test results (also called false positives) occur when the PSA level is elevated but no cancer is actually present. False positives may lead to additional medical procedures that have potential risks and significant financial costs and can create anxiety for the patient and his family. Most men with an elevated PSA test turn out not to have cancer; only 25 to 30 percent of men who have a biopsy due to elevated PSA levels actually have prostate cancer (3).

False negative tests: False negative test results (also called false negatives) occur when the PSA level is in the normal range even though prostate cancer is actually present. Most prostate cancers are slow-growing and may exist for decades before they are large enough to cause symptoms. Subsequent PSA tests may indicate a problem before the disease progresses significantly.

- PSA velocity: PSA velocity is based on changes in PSA levels over time. A sharp rise in the PSA level raises the suspicion of cancer.

- Age-adjusted PSA: Age is an important factor in increasing PSA levels. For this reason, some doctors use age-adjusted PSA levels to determine when diagnostic tests are needed. When age-adjusted PSA levels are used, a different PSA level is defined as normal for each 10-year age group. Doctors who use this method generally suggest that men younger than age 50 should have a PSA level below 2.4 ng/ml, while a PSA level up to 6.5 ng/ml would be considered normal for men in their 70s. Doctors do not agree about the accuracy and usefulness of age-adjusted PSA levels.

- PSA density: PSA density considers the relationship of the PSA level to the size of the prostate. In other words, an elevated PSA might not arouse suspicion if a man has a very enlarged prostate. The use of PSA density to interpret PSA results is controversial because cancer might be overlooked in a man with an enlarged prostate.

- Alteration of PSA cutoff level: Some researchers have suggested lowering the cutoff levels that determine if a PSA measurement is normal or elevated. For example, a number of studies have used cutoff levels of 2.5 or 3.0 ng/ml (rather than 4.0 ng/ml). In such studies, PSA measurements above 2.5 or 3.0 ng/ml are considered elevated. Researchers hope that using these lower cutoff levels will increase the chance of detecting prostate cancer; however, this method may also increase overdiagnosis and false positive test results and lead to unnecessary medical procedures.