Guidelines important in evaluating cytological samples for birds - DVM
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Guidelines important in evaluating cytological samples for birds


Coelomic cavity effusions are classified as pure transudates, modified transudates or exudates (nonseptic, septic, malignant or hemorrhagic) based upon cellularity, color, total protein and specific gravity. Pure transudates resulting from changes in oncotic pressure associated with hypoproteinemias, cardiac disease or hepatic cirrhosis are characterized by a low cellularity (total count less than 1,000 microliters), specific gravity of 1.020 or less, total protein of 3 g/dl or less, and a clear to pale- yellow color. Modified transudates have an increased cellularity (total cell counts greater that 1,000 microliters but less that 5,000 microliters) of mononuclear cells, granulocytes and reactive mesothelial cells, and protein content. Exudates typically have a high cellularity (greater than 5,000 microliters), high specific gravity (greater that 1.020) and total protein levels greater that 3 g/dl. The predominate cell type accompanying exudates may indicate the source.

Cytology of internal organs Tissue or fluid smears, squash preparations, aspiration or excisional biopsy are methods used to sample internal organs, such as the liver or spleen. Endoscopic or surgical laparoscopy techniques may be used to obtain samples. Splenic impressions generally reveal a significant amount of blood cells and heavy background of cellular debris. Liver aspirates are generally very cellular with hepatocytes in sheets or singles with a large amount of blood cells and free hepatocyte nuclei.

Bone marrow aspiration Nonregenerative anemias, blood dyscrasias, thrombocytopenia and neoplasia of the hematopoietic and reticulo-endothelial systems should be evaluated by bone-marrow examination. A preferred site for bone marrow aspiration in the avian patient is the proximal tibiotarsal bone. The widest part of the sternum may also be used. Additionally, a particular area may be aspirated if indicated by the presence of a lesion noted on radiographs. The proximal tibiotarsal bone is aseptically prepared, and a small incision is made in the skin. A spinal needle or hypodermic needle is inserted and advanced into the cnemial crest at either the level of insertion of the patellar tendon or perpendicular to the bone on the medial aspect. A 1 to 6-cc syringe is used to collect the sample. The needle and syringe are removed, and the marrow sample is placed on glass slides or cover slips and gently spread. Normal cells present in a bone-marrow aspirate include erythropoietic and granulopoietic cell lines in various stages of development lines, as well as thrombocytes, lymphocytes, osetoblasts and osteoclasts.

Dr. Jones is associate professor of avian and zoological medicine at the University of Tennessee's College of Veterinary Medicine. He is a diplomate of the American Board of Veterinary Practitioners — Avian Specialty. Dr. Jones' clinical interests include raptor medicine, orthopedic and soft-tissue surgery, avian nutrition and avian infectious diseases. He is also a master falconer with 15 years experience.


Source: DVM360 MAGAZINE,
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