Does the Renal biopsy necessary for me? The kidney function is well but there is a cyst in the left kidney and the urine check shows Occult Blood2+.

According to your description, the renal biopsy is necessary to confirm that you are not suffering from tumor. Renal biopsy is better but still you could have a CT scan to make sure whether the cyst is parenchymatous. A renal biopsy is also called a kidney biopsy. The test helps your physician to identify the type of kidney disease you have, how severe it is, and the best treatment for it. A renal biopsy can also be used to monitor the effectiveness of kidney treatments and see if there are any complications following a kidney transplant.Indeed, there are some complications after renal biopsy but the technology can treat them. Complications are rare, but no procedure is completely free of risk. If you have a kidney biopsy, your doctor will review a list of possible complications, which may include bleeding, infection and pain.
After the test, patients lie on their backs in the hospital for a few hours. During this time, the staff will monitor blood pressure and pulse and take blood samples to assess for blood loss. On rare occasions when bleeding does not stop on its own, a transfusion may be necessary to replace lost blood. Most patients leave the hospital the same day. Patients may notice some blood in their urine for 24 hours after the test.  http://www.tcm-kidney.com/ask-the-doctor/53.html
After the kidney biopsy, patients should lie on their backs—or stomachs if they have a transplanted kidney—for a few hours report any problems, such as
•bloody urine more than 24 hours after the test
•inability to urinate
•fever
•worsening pain
•faintness or dizziness
The treatment must be taken as soon as possible unless it is not a danger to our health. The traditional Chinese medicine is helpful to cure this problem. It is focus on the fundamental cause of the occult blood. If you haven’t try the traditional Chinese medicine, you can have a try and we hope you be healthy soon.