What’s Free PSA and How Is It Used to Diagnose Prostate Cancer?

PSA vs. free PSA

PSA是一种与精液结合并将其分解的酶。这使精液变得更液体。更液体的精液可以更轻松地将精子移至生殖过程中的女性输卵管。

PSA主要在您的前列腺中生产，并被释放到精液中。在射精期间，一些PSA通过前列腺的丰富血液供应进入您的血液。您体内有两种类型的PSA流通：

• 免费PSAt PSA是没有绑定o any proteins.
• Bound PSA是与蛋白质结合的PSA。

When your PSA is tested, it may be measured two ways:

• A免费PSA测试仅测量血液中未结合的PSA。
• APSA测试衡量您的总PSA，这意味着您的界限和自由。

免费PSA测试

如果您的PSA水平略有升高，则有时会进行免费的PSA测试，而不是活检。它也可以用来使您的医生了解如果您的癌症在治疗后恢复了癌症的侵略性。

PSA通常是通过手臂从手臂上取出的血液样本来测试的。样本将发送到实验室进行测试，结果将提供给您的医生。

PSA测试ing has a number of limitations.

• The PSA test is known to have a high rate of false positives.
• 当一个男人的PSA低于表明可能存在癌症的限制时，患有前列腺癌并不少见。
• About75 percentPSA升高的男性没有癌症。
• Normal PSA ranges were established primarily on white males, though PSA levels may vary depending on a man’s ethnicity.
• 如果PSA级别通过不同的实验室进行测试，或者技术人员使用不同的测试方法，则可能会发生变化。

PSA水平按年龄水平

以下是年龄正常的PSA水平：

您的测试结果是什么意思？

通常，您的PSA水平越高，自由PSA水平越低，患有前列腺癌的风险就越大。范围取决于年龄。随着年龄的增长，即使您没有前列腺癌，您的PSA水平也会上升。

医生还研究了PSA的其他方面，包括：

• PSA速度。PSA级别的变化（称为PSA速度）是另一个考虑因素。如果您的PSA水平迅速升高，那么您患前列腺癌的风险就会更大。
• 加倍。您的PSA越来越多，您患前列腺癌的风险就越大。医生还使用加倍时间来确定已经被诊断出患有这种疾病的男性中的前列腺癌是否扩散。

免费PSA

免费PSAis measured as the proportion of free PSA to total PSA. Below is a table outlining the likelihood of finding prostate cancer based on the percentage of free PSA in men with a total PSA between 4ng/mL and 10 ng/mL, according to the 美国医学协会杂志 .

免费PSA与活检

平均而言，免费的PSA测试可以减少对20 percent不必要的活检。它还可以帮助确定您患有前列腺癌是否更有可能。如果您的结果表明您可能患有前列腺癌，那么您仍然需要活检来确认前列腺癌的诊断。

When you have a prostate biopsy, a specialist called a urologist will take small samples of tissue from your prostate gland using a special hollow needle. The tissue is examined under a microscope to see if cancer cells are present.

副作用很常见，但很少严重。您可能会经历：

• 活检部位出血
• 尿液或精液中的血液
• trouble urinating

利弊

进行免费的PSA测试是有几个优点，而不是对总PSA水平升高进行活检。这些包括：

• A prostate biopsy is an invasive procedure that carries a greater risk of infection and complications.
• Although biopsies are usually performed using local anesthetic, most men find them uncomfortable. Some men report pain.
• 活检的成本明显高于免费PSA测试。

The primary advantages of a biopsy are that if you have cancer, tissue samples taken during the biopsy can provide more information about your condition. A biopsy can provide your doctor with information about the size of the tumor and give your doctor an idea of how aggressive the cancer is. Your doctor can use results from a biopsy to assign a stage and grade for your cancer, which will help you and your doctor decide your best treatment options.

费用

Unless you have symptoms of prostate cancer or a family history that puts you at greater risk, a free PSA test can be a logical step if your total PSA levels are high. The test may eliminate the need for a biopsy, which is a far more expensive procedure.

费用for medical services vary from region to region, and even from doctor to doctor. A free PSA test is a simple blood test that usually cost less than 100 dollars. You may have to pay for an office visit, as well. An office visit will almost certainly be more expensive if you see a urologist instead of your primary care doctor.

Even if performed in your urologist’s office rather than an ambulatory care facility, a biopsy will be significantly more expensive. Fees will include:

• 咨询泌尿科医生
• ultrasound used to help guide the needle biopsies
• 审查活检的病理咨询
• miscellaneous supplies

您应该有免费的PSA测试吗？

如果您的PSA总水平很高，那么进行免费的PSA测试而不是直接进行活检通常是一个很好的下一步。不过，最终，这是您和您的医生应该讨论的问题。