Renal biopsy provides important diagnostic information that can alter management in 50-60% of patients. The procedure involves inserting a biopsy needle into the kidney under ultrasound guidance to obtain tissue samples. Key factors in ensuring diagnostic adequacy include obtaining a sufficient number of glomeruli (typically 5 or more) and dividing samples appropriately for light microscopy, immunofluorescence, and electron microscopy. Patients are monitored post-biopsy for bleeding complications, which occur in less than 1% and typically present as visible hematuria or need for blood transfusion. Renal biopsy is generally safe but strict post-biopsy rest and follow-up are important.

1. Renal Biopsy

2. Why Biopsy?
• The role of the renal biopsy has been much
debated.
• Early studies suggested that renal biopsy
provided diagnostic clarity in most patients,
but that this information did not alter
management, except for those with heavy
proteinuria or systemic disease.
• More recent prospective studies have
suggested that the renal biopsy identifies a
diagnosis different from that predicted on
clinical grounds in 50% to 60% of patients and
leads to a treatment change in 20% to 50%.
• This is particularly apparent in patients with
heavy proteinuria or AKI, more than 80% of
whom have biopsy findings that alter their
management.

3. History
• The first renal biopsies from living patients were obtained surgically as early as 1896 usually during the
course of operations to decapsulate the kidneys in patients with Bright disease, to relieve the ‘intrarenal
oedema’, a procedure popular during the first two decades of the twentieth century.
• The first needle renal biopsies were obtained accidentally at attempted liver biopsy in the 1940s.
• This led Alwall to use the technique to target the kidney directly using the aspiration biopsy needle
developed by Iversen in 1944 (but reported in 1952.
• It was the landmark paper by Iversen and Brun in 1951 that popularized the use of the percutaneous
renal biopsy.
• The technique was refined including positioning the patient prone (originally patients were biopsied
sitting) and using a Vim–Silverman (non-aspiration) needle with improved success and tissue adequacy.
• Originally imaging included plain films before and during the procedure, insufflation of perirenal air to
aid localization, fluoroscopy, and the use of intravenous urography.
• Biopsies are now generally performed using real-time ultrasound and a disposable needle with or
without a biopsy gun.
• The percutaneous renal biopsy is now a routine and essential diagnostic tool guiding diagnosis and
prognosis.

5. Indications of Renal Biopsy

6. Indications

7. Special Scenario

8. Diabetes
• The UKPDS study found that in people with type 2 diabetes the prevalence of
microalbuminuria, macroalbuminuria, or an elevated creatinine/renal failure was 25%,
5%, and 0.8% respectively at 10 years following diagnosis.
• Patients with diabetic nephropathy usually have evidence of retinopathy and/or
neuropathy and when these are present, a biopsy is not usually indicated.
• In the absence of these complications or with rapid-onset nephrotic syndrome, a short
duration of (diagnosed) diabetes and possibly with significant haematuria or systemic
disease, a biopsy is indicated to determine if another treatable condition is present.

9. Repeat Renal Biopsy
• The pathologic changes in lupus nephritis may evolve, necessitating treatment
adjustment.
• In addition, corticosteroid-resistant, corticosteroid dependent, or frequently relapsing
MCD may represent a missed diagnosis of FSGS, which may be detected on repeat
biopsy.
• Some nephrologists think repeat biopsy in patients who have had aggressive
immunosuppressive therapy of crescentic GN can help determine the most appropriate
next line of therapy.

10. Pregnant patient
• Kidney disease in pregnancy can present with either proteinuria or hematuria or an acute
increase in Scr level.
• The time relationship of AKI patterns in pregnancy allows for probable diagnosis based
on history, timing of symptom onset, and hematologic and serologic evaluations.
• Biopsies in pregnant patients are generally safe, with studies showing a low complication
risk before 20 weeks’ gestation and case reports showing on average a 2-fold increase in
bleeding after 20 to 25 weeks’ gestation.
• Ideally, the pregnant patient should undergo a percutaneous ultrasound-guided kidney
biopsy because CT guided and transjugular biopsies involve radiation exposure.
• The technique is similar to that for the nonpregnant patient with the exception of
positioning favoring the lateral decubitus or sitting upright position as opposed to the
prone position after the 20th week of pregnancy.

11. Cirrhotic patient
• Patients with cirrhosis are at risk for developing AKI or disease.
• The patient with liver failure may present with significant bleeding risk due to a low
platelet count or coagulopathy and elevated INR.
• Cirrhotic patients appear to have increased risk for post biopsy bleeding.
• However, if a percutaneous biopsy is necessary due to lack of interventional expertise, a
single pass yielding 1 core can be obtained and used for light microscopy,
immunohistochemistry, and electron microscopy, thereby minimizing the risk for
bleeding in this cohort of patients in which risk for bleeding has not been fully realized.

12. Contraindications

13. Pre-Biopsy work up

14. Procedure

15. Percutaneous Renal Biopsy
• The kidney biopsy is performed by nephrologists with continuous (real-time) ultrasound
guidance and disposable automated biopsy needles.
• 16-gauge needles is used as a compromise between the greater tissue yield of larger
needles and the trend toward fewer bleeding complications of smaller needles.
• The patient is prone, and a pillow is placed under the abdomen at the level of the
umbilicus to straighten the lumbar spine and splint the kidneys.
• Ultrasound is used to localize the lower pole of the kidney where the biopsy will be
performed (usually the left kidney).
• An indelible pen mark is used to indicate the point of entry of the biopsy needle.
• The skin is sterilized with povidone-iodine (Betadine) or chlorhexidine solution.
• A sterile fenestrated sheet is placed over the area to maintain a sterile field. Local
anesthetic (2% lidocaine [lignocaine]) is infiltrated into the skin at the point previously
marked.

16. Biopsy Gun

17. Percutaneous Renal Biopsy
• While the anesthetic takes effect, the ultrasound probe is covered in a sterile sheath.
• Sterile ultrasound jelly is applied to the skin, and, under ultrasound guidance, a 10-cm, 21-gauge needle
is guided to the renal capsule and further local anesthetic infiltrated into the perirenal tissues, then along
the track of the needle on withdrawal.
• A stab incision is made through the dermis to ease passage of the biopsy needle.
• As the needle approaches the capsule, the patient is instructed to take a breath until the kidney is moved
to a position such that the lower pole rests just under the biopsy needle, and then to stop breathing.
• The biopsy needle tip is advanced to the renal capsule, and the trigger mechanism is released, firing the
needle into the kidney.
• The needle is immediately withdrawn, the patient is asked to resume breathing, and the contents of the
needle are examined
• A second pass of the needle is usually necessary to obtain additional tissue for immunohistologic
examination and EM.
• If insufficient tissue is obtained, further passes of the needle are made, passing the needle more than four
times is associated with a modest increase in the postbiopsy complication rate.
• Once sufficient renal tissue has been obtained, the skin incision is dressed and the patient rolled directly
into bed for observation

20. Other Approaches
• Ultrasound can be used only to localize the kidney and determine the depth and angle of
approach of the needle and perform the biopsy without further ultrasound guidance.
• The success and complication rates appear to be no different from those seen with
continuous ultrasound guidance.
• For technically challenging biopsies, CT can be used to guide the biopsy needle.
• For obese patients and patients with respiratory conditions who find the prone position
difficult, the supine anterolateral approach recently has been described.
• Patients lie supine with the flank on the side to be sampled elevated by 30 degrees with
towels under the shoulder and buttocks.
• The biopsy needle is inserted through the inferior lumbar triangle, bounded by the
latissimus dorsi muscle, 12th rib, and iliac crest.
• This technique provides good access to the lower pole of the kidney, is better tolerated
than the prone position by these patients, and has a diagnostic yield and safety profile
comparable to that of the standard technique for native renal biopsy.

22. Laparoscopic Kidney Biopsy
• There are some patients in whom a percutaneous approach is associated with unacceptable
risk.
• In these cases, kidney biopsy under direct vision is a reliable option.
• Kidney biopsy under direct vision can be performed with an open incision or laparoscopically.
• This method allows positive identification of kidneys for a macroscopic diagnosis, and biopsy
and homeostasis are better achieved under direct view.
• The possible indications for laparoscopic kidney biopsy include the following:
• Failed percutaneous biopsy
• Chronic anticoagulation state/coagulopathy
• Morbid obesity
• Solitary kidney
• Multiple bilateral kidney cysts
• Kidney artery aneurysm
• Uncontrolled hypertension

23. Laparoscopic Kidney Biopsy
• Procedure
• The biopsy is performed under general anesthesia
with the patient in the lateral decubitus position.
• A two-port technique is used: a 10-mm laparoscopic
port is placed above the iliac crest in posterior
axillary line and a 5-mm port is placed at the same
level in the anterior axillary line.
• The lower pole of kidney is exposed after minimal
blunt retroperitoneal dissection. Laparoscopic cup
biopsy forceps are used to take multiple superficial
cortical biopsies.
• The biopsy site can be fulgrated with argon beam
coagulator and a sheet of oxidized cellulose can be
applied there upon.

24. Trans Jugular Kidney Biopsy
• The transjugular route has been used for thousands of liver biopsies since its description
in 1964.
• Even when used for severely ill patients, morbidity and mortality rates were extremely
low, partly because when hemorrhage occurs. the blood reenters the circulation.
• In 1989, Frederic Mal did a liver biopsy, which the pathologist reported as kidney tissue.
This led to the idea of transjugular kidney biopsy.
• Simultaneous liver–kidney biopsy can be performed, especially in disorders involving
both liver and the kidney.
• The following are relative advantages of transjugular biopsy:
• Safer as needle passes into vein and away from major vessels. Any bleed directs to vein
• Capsular perforation managed with elective coil embolization.
• Disadvantages: Arterio-calyceal bleed, samples are small and difficult to interpret

25. Graft Biopsy
• Biopsy of the transplant kidney is facilitated by the proximity of the kidney to the anterior
abdominal wall and the lack of movement on respiration.
• It is performed under real-time ultrasound guidance with use of an automated biopsy needle.
• It is important to confirm that the transplanted kidney is in the normal extraperitoneal
position— occasionally it will be intraperitoneal (simultaneous pancreas and kidney
transplants in particular), and bowel injury becomes a potential hazard.
• In most patients, the renal transplant biopsy is performed to identify the cause of acute
allograft dysfunction. In these circumstances, the goal is to identify acute rejection, and
therefore the diagnosis can be made on a formalin-fixed sample alone for light microscopy.
• If vascular rejection is suspected, a snap-frozen sample for C4d immunostaining also should
be obtained (although some laboratories can detect C4d on formalin-fixed material).
• If recurrent or de novo GN is suspected in patients with chronic allograft dysfunction,
additional samples for EM and immunohistologic examination should be collected

26. Specimen

27. Quality of the sample
• The use of a “dissecting microscope” can be of assistance in assessing sample adequacy.
• Another alternative is the use of a standard light microscope.
• The tissue is placed on a glass slide with normal saline and examined with or without a
cover slip on a wet mount.
• A trained observer can recognize fat, skeletal muscle, and other non-kidney tissue.
• Knowledge of the glomerular content of the sample can also guide division of tissue for
the various test modalities.

28. Renal biopsy specimen as seen with a dissecting microscope.
(a) Renal cortex, note the glomeruli, recognized as round red areas
(b) Renal medulla, reddish vasculature is present but no glomeruli seen

30. Dividing the Sample
• Cortex mainly contains glomerulus and medulla mainly contains tubules and interstitium
• In the absence of direct glomerular visualization, a standard protocol for dividing the tissue
obtained at each ‘pass’ should be used to avoid inadequate glomerular sampling for LM, IF or EM.
• The standard approach is to first procure tissue for EM from each core by removing 1mm cubes
from the ends.
• First core can be cut in half by cross sectioning and the larger piece placed for LM; the smaller
portion is saved for IF evaluation.
• If a second core is obtained, the ends should be taken for EM and the specimen again divided
almost in half with the larger tissue core now kept for IF and the smaller for LM.
• Alternatively, if both cores contain cortex, one core can used for LM and one core for IF.
• If tissue is limited, the clinical differential diagnosis may drive the division of material, for example,
in cases of RPGN, an attempt to secure sufficient material for IHC to rule out antiglomerular
basement membrane antibodies is important.
• Although artefacts will be induced, frozen tissue used for IF can be subsequently processed for
either LM or EM and, depending upon the questions to be addressed, useful information can still
be obtained.

32. Adequacy of the Sample
• In the assessment of a renal biopsy, the number of glomeruli in the sample is the major
determinant of whether the biopsy will be diagnostically informative.
• the probability that FSGS is not present in a patient with nephrotic syndrome and
minimal changes on the biopsy specimen depends on the actual proportion of abnormal
glomeruli in the kidney and the number of glomeruli obtained in the biopsy specimen.
• For example, if 20% of glomeruli in the kidney have sclerosing lesions and five glomeruli
are sampled, there is a 35% chance that all the glomeruli in the biopsy specimen will be
normal and the biopsy will miss the diagnosis. By contrast, in the same kidney, if 10 or 20
glomeruli are sampled, the chance of obtaining all normal glomeruli is reduced to 10%
and less than 1%, respectively, and the biopsy is more discriminating.
• Unless all glomeruli are affected equally, the probability that the observed involvement in
the biopsy specimen accurately reflects true involvement in the kidney depends not only
on the number of glomeruli sampled but also on the proportion of affected glomeruli

33. Adequacy of the Sample
• Sample size – two cylinders with a
minimal length of 1 cm and a diameter of
at least 1.2 mm are needed.
• Needle gauge: 18 gauge (G).
• Number of glomeruli for adequate
diagnosis:
• For glomerular lesions: 5
• For tubulointerstitial lesions: 6-10.
• For transplant kidney: 7

34. Post Biopsy Monitoring
• After the biopsy, the patient is placed supine and subjected to strict bed rest for 6 to 8
hours.
• The blood pressure is monitored frequently the urine examined for visible hematuria, and
the skin puncture site examined for excessive bleeding.
• If there is no evidence of bleeding after 6 hours, the patient is sat up in bed and
subsequently allowed to ambulate.
• If visible hematuria develops, bed rest is continued until the bleeding settles.
• Advise minimal activity for 48 hours after biopsy and avoidance of contact sports and
activities requiring straining for a total of 2 weeks.

35. Post Biopsy Monitoring
• A study showed that only 67% of major complications, defined as those that required
either a blood transfusion or an invasive procedure or resulted in urinary tract
obstruction, septicemia, or death, were apparent by 8 hours after biopsy.
• These authors concluded that the widespread application of an early discharge policy
after renal biopsy is not in the patient’s best interest and that a 24-hour observation
period is preferable.
• How ever if the risk of complication is stratified (high risk being impaired renal function
(eGFR <30 ml/min), small kidneys, and uncontrolled hypertension) outpatient renal
biopsy is acceptably safe when a low-risk patient group is selected.

36. Complications
Complications in 9474 Native Kidney Biopsies
Complication Percentage
Visible hematuria 3.5
Need for blood transfusion 0.9
Need for intervention to control bleeding 0.7 (0.6 angiographic; 0.1 surgical)
Death 0.02

37. Pain
• There may be dull ache around the needle entry site when the local anesthetic wears off
after renal biopsy.
• More severe pain in the loin or abdomen on the side of the biopsy suggests significant
perirenal hemorrhage.
• Opiates may be necessary for pain relief, with appropriate investigation to clarify the
severity of the bleed.
• Patients with visible hematuria may develop clot colic and describe the typical severe
pain associated with ureteral obstruction.

38. Hemorrhage
• A degree of perirenal bleeding accompanies every renal biopsy.
• The mean decrease in hemoglobin after a biopsy is approximately 1 g/dl.
• Significant perirenal hematomas are almost invariably associated with severe loin pain.
• Both visible hematuria and painful hematoma are seen in 3% to 4% of patients after
biopsy.
• The initial management is strict bed rest and maintenance of normal coagulation indices.
• If bleeding is brisk and associated with hypotension or prolonged and fails to settle with
bed rest, renal angiography should be performed to identify the source of bleeding. Coil
embolization can be performed during the same procedure, and this has largely
eliminated the need for open surgical intervention and nephrectomy

39. Arteriovenous Fistula
• Most post biopsy arteriovenous fistulas are detected by Doppler ultrasound or contrast-
enhanced CT and, when looked for specifically, can be found in as many as 18% of
patients.
• Most are clinically silent and more than 95% resolve spontaneously within 2 years
• Other complication
• A variety of rare complications have been reported, including biopsy performed on other
organs (liver, spleen, pancreas, bowel, gallbladder),
• pneumothorax,
• hemothorax,
• calyceal-peritoneal fistula,
• dispersion of carcinoma, and
• Page kidney (compression of kidney by perirenal hematoma leading to renin-mediated
hypertension).

40. Thank You