Kidney Biopsy is a procedure in which a very tiny piece of the kidney is removed for examination under a microscope for diagnosis of the kidney disease. It may also inform us about prognosis (future course ) of the disease, severity of disease and suggest ways of treatment. The information given below is relevant for cases of native kidney biopsy.
Indications for kidney biopsy:
When urine shows high levels of protein, RBCs or other abnormalities like casts.
Unexplained acute kidney injury
Some cases of chronic kidney disease
renal transplant dysfunction
The procedure of kidney biopsy:
Patients consent is taken.
Blood group is checked.
Tests are done to see that the bleeding and clotting is normal
Ultrasonography to confirm that both kidneys are
normal or large,
more or less symmetrical,
there is no stone disease, tumour or cyst etc.
The person is made to lie down on his abdomen with the back facing up. After cleaning the area with antiseptics, the site of biopsy is injected with local anesthetic drugs. After a few minutes, a biopsy needle is gradually inserted till it is lying very close to the cortex of the kidney and the site is confirmed by USG. Then the trigger is pressed. This inserts the needle for a distance of 10-15 mm in the kidney and a piece of tissue (16 to 18 gauge in core diameter ) is trapped in the needle. The needle is then withdrawn and the site dressed in clean sterile gauze. It is pressed for a few minutes with compression of about 1to 2 kgs and patient then turned to lie on his back. His USG is checked for any bleeding after biopsy and shifted to the ward.
He is kept under observation for 24 hrs (sometimes only 6 hrs) for any complications. If none, he or she is discharged and called to attend the hospital with biopsy report.
Processing and transport of biopsy:
The tissue is sent in formalin/ glutaraldehyde or cold saline for different tests. It is usually seen by light microscope and immunofluorescent staining and if available, electron microscopy.
Risks of kidney biopsy:
The common risk is bleeding. It occurs in most cases but usually is insignificant. If a large amount of blood is lost, patient may require blood transfusion and rarely if bleeding is not controlled, the kidney may have to even be removed. Nowadays such occurrences are rare.
The biopsy site or kidney may get infected, lacerated and even deaths after biopsy have been reported. The risk of death is about 1in 1000 to 1 in 10000 at various centers.