AmeriPath offers specialized nephropathology diagnostic services nationwide focusing on renal and transplant pathology. We provide exceptional technical and professional services for renal biopsy diagnosis to nephrologists and other physician who rely on the understanding of our services. Our board-certified, fellowship-trained nephropatholgist has years of experience interpreting renal biopsies. With our focus on timely communication and reporting, in addition to proven expertise, our customer satisfcation is outstanding in the industry.

Nephropathology Services

What is Nephropathology?

Nephropathology is a pathology subspecialty focusing on the microscopic diagnosis and interpretation of kidney biopsies. Most of nephropathology focuses on understanding the key features associated with the disease processes seen in patients’ native kidneys as well as those patients who have received transplanted kidneys.

Why is a biopsy necessary?

Clinical information alone is often insufficient for a diagnosis. The clinical information must often be combined with the diagnosis of a kidney biopsy to understand the disease process. Together, the clinical information and the examination of the kidney biopsy provide insights into the clinical disease and the process responsible for suspected kidney injury, damage and disease.

How can I prevent further renal injury?

There are a few ways to protect your kidneys from damage. Many of them have probably already been discussed with you (i.e. weight loss, reducing sodium intake, avoiding high cholesterol diets, stopping smoking, etc.). Depending on the nature of your kidney disease, there may be additional steps you can take to protect yourself from additional renal injury. Please consult with your treating physician to find what additional steps can be taken to help prevent further injury to your kidneys.

Renal Transplant Biopsies

All renal transplant biopsies are routinely evaluated for both humoral and cellular rejection. Cellular rejection is usually highlighted by routine histochemical stains (i.e. H&E, PAS, Trichrome and Jones silver stains); however, humoral rejection is often more subtle. It typically requires more specialized staining. For humoral rejection, additional studies include:

– C4d by immunohistochemistry

– C4d by indirect immunofluorescent analysis

In general, if the patient has been transplanted for less than one year, a modified workup will include the light microscopy plus a C4d immunohistochemistry marker. The C4d is performed by immunohistochemistry only when frozen section tissue is not available. Wet tissue that has been submitted in formalin (or Bouin’s) fixative can be used to detect the presence of C4d by immunohistochemical markers; however, frozen section tissue using the indirect immunofluorescent staining approach is preferred.

If transplantation has occurred greater than one year from the time of the biopsy, the likelihood of recurrent of a native kidney disease is increased. For this reason, a full work-up like that seen for a native kidney biopsy is recommended. This includes light microscopic, immunofluorescent and electron microscopic analysis plus C4d. Since C4d by the indirect immunofluorescence approach is more sensitive, it is performed on the frozen section tissue.

In some cases, our laboratory can arrange to provide the technical services for your laboratory (technical only). For additional information on these services, please contact us.

Native Kidney Biopsies 

AmeriPath Nephropathology Diagnostics employs a number of histochemical and immunological approaches to identifying diseases of the native kidney. These approaches include the following routine studies:

  • Routine light microscopy analysis
    • H&E stain
    • PAS stain
    • Masson’s Trichrom
    • Jones Silver stain
    • Congo Red (when indicated)
  • Direct immunofluorescence (DIF) analysis
    • IgG immunoglobulin
    • IgA immunoglobulin
    • IgM immunoglobuiln
    • C1q complement fragment
    • C3 complement fragment
    • Fibrinogen
    • Kappa light chain
    • Lambda light chain
  • Indirect immunofluorescence (IF) analysis
    • C4d complement fragment (for transplanted kidneys)
  • Transmission electron microscopic (TEM) analysis
    • Toluidene-blue basic fuschin stain
    • Uranyl-acetate/lead-citrate.

Occasionally, the disease process may need additional markers for diagnostics and/or prognostics. Our extended panels include:

  • IgG subtyping
  • Alports panels
  • AA amyloidosis (SAA)
  • Transthyretin
  • Apolipoprotein (s) AI&AII
  • Fibrinogen alpha chain
  • Lysozyme


The standard of care for renal biopsies includes the processing and interpretation of light microscopy. This is typically done by staining tissue with H&E, PAS, Trichrome and Jones Silver stains.

While we prefer to fully process the “wet tissue” specimens in our laboratory, we understand that certain hospital and/or physician organizations prefer to review the histology prior to it being sent for an expert opinion.

When a specimen has already been partially processed in an outside laboratory, we will review and process the remaining specimen for H&E, PAS, Trichrome and Jones Silver stains. If we receive tissue with additional “outside” slides, we will render a diagnosis on the “outside” processed slides as well.


Inflammatory diseases of the kidney show a strong predilection for deposition of antibodies and other associated proteins of the immune response. Since these molecules are very hard to detect using traditional immunohistochemistry, a more sensitive technique known as immunofluorescence, is employed to elicit the casual agents of the inflammatory disease process.

The markers of inflammation routinely used to diagnosis renal disease include antibodies to:

  • Albumin
  • IgG
  • IgA
  • IgM
  • C1q
  • C3
  • Fibrinogen
  • Kappa light chain
  • Lambda light chain

Additional markers are sometimes necessary to further classify the disease process. Some of these markers include IgG subtypes. Other markers are occasionally needed to help differentiate among the various subtypes of amyloidosis. These markers will be discussed with the treating clinician when necessary.

In renal transplant biopsies, a C4d immunofluorescent antibody is used (indirect method).

Electron Microscopy

Since the kidney filters the human’s body waste, very small particles can get trapped in the filtering structures (glomeruli). These particles are too small for the naked eye to interpret; however, differentiating among the different types of particles deposited is essential in making the correct diagnosis and getting the patient on the correct treatment pathway. To help differentiate between these various possibilities, a very powerful instrument, known as the transmission electron microscope (TEM), is used to detect the presence of these very small particles.

In order to process tissue for ultrastructural studies using a transmission electronic microscopy, the tissue needs to be processed first using a special histochemical stain called a toluidene-blue basic fuschin stain, and then it needs to be stained with a radioactive stain uranyl-acetate, combined with lead-citrate. These stains help produce the electron-density needed for an electron to bounce off the tissue. This results in an image that is projected onto a fluorescent screen that can be interpreted by the human eye.

The ultrastructural findings often provide the most crucial evidence for which a diagnosis rests, and the field of nephropathology has depended on this technology for many years.

In some cases, “technical only” processing with images can be performed and the results discussed with an outside laboratory. Please contact for us more information.

Handling and Sending Tissue

Renal Biopsy Specimen Handling and Transport

AmeriPath’s nephropathology diagnostics offers a convenient, detailed and informative specimen handling and transport guide for our nephrologists and interventional radiologists. This handbook is designed to help optimize your partnership with AmeriPath. A quick review of the guide is below.


  • Red top (Bouin’s) vial: Bouin’s fixative for specimen submitted for routine light or electron microscopy
  • Green top (Michel’s) vial: Immunofluorescent Transport Media (ITM) used for specimens submittted for Direct and Indirect Immunofluorescence
  • Grey top (Glutaraldehyde) vial: Glutaraldehyde fixative for specimen submitted for electron microscopy
  • Cold pack, refrigerate prior to use
  • Biohazards bag

Specimen Collection

  1. Open Package
    • Remove vials and complete all paperwork included in kit, including patient history form and billing information
    • Label vials with patient information
  2. Obtain renal tissue (cortex) – 3 cores are optimal, but 2 are acceptable
  3. Take clean forceps and place one entire core in Michel’s IF Transport Media (green top) vial first. Place cap on and fasten. This is to prevent any cross-contamination of the tissue with the formalin. If even a drop of formalin gets on the IF tissue, it will ruin that portion of the renal panel
  4. Next, rinse forceps with water and wipe them off. Replace the remaining tissue in the formalin (red top) vial. Place cap and fasten.

NOTE: You do not need to cut the tissue. Our lab technicians will cut the tissue and appropriately triage if for light and electron microscopy. 


  1. Place both vials back into kit box and place ice pack on top
  2. Close box and place it in the labeled FedEx envelope, along with completed paperwork.
  3. Contact FedEx for pickup
  4. Then, call us with the tracking number to let us know that the specimen is on its way.

*Please do not hesitate to contact us with any questions at 405.841-7875. Ask for the Nephropathology department 


  • For courier service:
    • Please contact our laboratory for local pick-ups
  • For overnight shipping:
    • Place specimen transport kit inside FedEx diagnostic specimen bag
    • Complete FedEx air bill and mark Priority Overnight (next morning) delivery
    • If specimen is being shipped on Friday, be sure to mark SATURDAY delivery
    • Secure air bill to outside of FedEx bag and call FedEx pick-up at 1.800.463.3339
    • Please notify client services at 1.800.281.8077 with air bill #, patient’s name and specimen(s) submitted for specimen tracking purposes

Practice Location

AmeriPath – Nephropathology Diagnostics

c/o: Diagnostic Pathology Services, Inc

225 N.E. 97th St., Suite 600

Oklahoma City, OK 73114

P: 1.405.841.7875