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The MedStar Georgetown University Hospital Pathology Department provides a wide range of clinical laboratory services.

  • Molecular Diagnostics Laboratory (MDL): A comprehensive diagnostic laboratory that provides molecular-based tests for cancer, infectious diseases, and genetics. Below are descriptions of all the laboratories located with in the MDL. For information regarding test ordering, please call: (202) 784-3614
    1. Flow Cytometry: Flow cytometry is currently used to identify leukemia/lymphoma, myelodysplastic syndromes (MDS), and paroxysmal nocturnal hemoglobinuria (PNH) phenotypic markers. The laboratory utilizes panels designed to diagnose these conditions, by means of monoclonal antibodies directed against various antigenic markers, such as cluster differentiation (CD) antigens. The flow cytometric results are used in conjunction with morphological data to make a diagnosis.


      Kappa and Lambda light chain in a patient that demonstrates clonality.

       
    2. Immunohistochemistry: Staining tissue sections with antibodies and chromogen to highlight the presence (or absence) of certain antigens. We currently have over 100 antibodies in our inventory; please refer to the test menu for a complete listing.
      • Unusual viral antigen amplification: We are currently testing for various viruses including, but not limited to, HHV-6, HHV-7, and EBV.
    3. PCR: Detection of genetic rearrangements and/or translocations through polymerase chain reaction (PCR), reverse transcriptase PCR (RT-PCR) or real-time (quantitative) PCR (Q-PCR).
      • High-Risk HPV testing: We are currently testing for HPV, types 16 and 18. Certain cancers, cervical, head and neck, develop due to the contraction of high-risk HPV.
      • KRAS and BRAF: KRAS Mutation Analysis analyzes codons 12 and 13 of the KRAS gene by single nucleotide primer extension.
    4. FISH: cytogenetic technique which is used to detect and localize the presence or absence of specific DNA sequences on chromosomes. It uses fluorescent probes which identifies amplified Her2-neu and t(1;19) gene copies in cases of aggressive breast cancers and leukemias, respectively. Fluorescence microscopy is used to determine if and where the fluorescent probe binds to the chromosome. FISH is often used for finding specific features in DNA. These features can be used in genetic counseling, medicine, and species identification.
    5. ACIS: An image analysis instrument which enables us to quantitatively analyze breast cancer hormone receptor and Her-2/neu gene amplification levels. Treatment options are dependent upon the results of the image analysis.
  • Electron Microscopy: Ultra-structural analysis to help primarily in the diagnosis of renal disease, metabolic storage disorders, cancer and respiratory disorders (ciliary morphology).


    An electron micrograph of a native kidney biopsy taken from a patient with membranous lupus nephritis, WHO class V, showing typical "wall-to-wall" sub-epithelial immune deposits (strongly IgG+ by immunofluorescence) in glomerular basement membranes.

     
  • Immunofluorescence: A technique allowing the visualization of a specific protein or antigen in cells or tissues by binding a specific antibody chemically conjugated with a fluorescent dye such as fluorescein isothiocyanate (FITC). This diagnostic tool is used to analyze a variety of tissues, most frequently in our facility, renal and dermatologic specimens.


    Immunofluorescence staining of a native kidney biopsy with the antibody, IgA.


    Immunofluorescence staining of a native
    kidney biopsy with the antibody, IgG.

     
  • Cytology: Provides diagnostic service for cervical (Pap) smears, body fluids, urines, cerebrospinal fluids, bronchoalveolar lavages (BALs), GI brushings and fine needle aspirations. Cytology specimens are centrifuged to collect the cells and then processed to produce mono-layered smears for microscopic evaluation. When necessary, additional mono-layered slides are made for special studies/stains.
    1. Fine Needle Aspirations (FNA): Fine Needle Aspiration is a procedure performed by the cytopathologist using a very thin needle (usually a 25 or 23 gauge), which is smaller than the one used to draw blood. The mass or lump to be aspirated is palpated and immobilized. The needle is then inserted into the mass and cells are extracted. The material is then expelled onto a glass slide, and into a special solution for additional smears to be prepared. The needle remains in the mass for about 5 seconds during each needle stick. The size of the mass determines the number of needle sticks necessary. The lesion is usually aspirated three times to obtain both a representative and an adequate sample. There is no need for anesthesia. The procedure is usually well tolerated, although there may be minor discomfort, which varies from patient to patient.
  • Surgical Pathology: Responsible for the gross and microscopic examinations of all surgically removed tissue. Pathology frozen sections for rapid diagnostic pathology are also carried out in surgical pathology. The surgical pathology system affords the residents maximum exposure to diagnostic microscopic diagnosis.
  • Histology: Provides diagnostic, imbedding and staining services for all surgical specimens, endoscopies and biopsies. This service is available to the Georgetown University Hospital and the community. The laboratory is on staff from 3:00 am to 6:00 pm, Monday through Friday.