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1368 Neospora Serology Neutrophils (Neutrophilia, Neutropenia)

Lab Artifacts Relative Cost: $$$ are no red blood cells in urine sediment and
Must distinguish myoglobinuria from other Pearls no evidence of hemoglobinemia, a positive
VetBooks.ir dipstick such as hematuria, hemoglobinuria, • Myoglobinuria may be distinguished from • Myoglobinuria may be confirmed with an
blood result on urine dipstick suggests
causes of positive reaction for blood on urine
myoglobinuria by process of elimination.
hemoglobinuria and hematuria by check-
and substances that cause a false-positive
reaction (high bilirubin concentration, con-
(hematuria) or absence of red blood cells and
tamination of urine with oxidizing agents in ing the urine sediment for the presence ammonium sulfate precipitation test on
urine, and checking for additional evidence
disinfectants, leukocytes, bacteria, peroxidase, evaluating the color of the plasma or serum of muscle damage (e.g., elevation of serum
or iodine) for a pink discoloration (hemoglobinemia). creatine kinase). Addition of ammonium
Hemoglobin in plasma binds haptoglobin sulfate to urine to 80% concentration will
Specimen Collection and Handling and is largely retained in the circulation (not cause hemoglobin to precipitate. Myoglobin
• Myoglobinemia: serum (red top tube), hepa- readily cleared by glomerular filtration). does not precipitate and will continue to
rinized plasma (green top tube), or EDTA Pink discoloration of the serum indicates give a positive occult blood result on urine
plasma (lavender top tube). Refrigerate at hemolysis and suggests hemoglobinuria as dipstick.
2°C-8°C. cause for positive urine dipstick blood result.
• Myoglobinuria: 1 mL urine (clean container Myoglobin is readily excreted in the urine, so AUTHOR: Ruanna E. Gossett, DVM, PhD, DACVP
EDITOR: Lois Roth-Johnson, DVM, PhD, DACVP
without additives) the serum is usually clear to yellow. If there

Neospora Serology

Definition • Most dogs with confirmed neosporosis have Relative Cost: $$$
Detection of serum antibody to Neospora titers ≥ 1:200. High titers have been found in Pearls
caninum by IFA or ELISA clinically normal dogs, suggesting subclinical
disease. • Diagnosis is sometimes made via observation
Physiology of tachyzoites of N. caninum in biopsy/
N. caninum is a coccidian parasite whose Next Diagnostic Steps to Consider necropsy tissue or in cytologic preparations.
morphology is identical to Toxoplasma gondii if Levels Are High Although the morphology of the tachyzoites
under light microscopy. Clinical manifestations Treatment for neosporosis if clinical signs are of N. caninum and T. gondii is identical,
of N. caninum in dogs are primarily neurologic compatible with this disease. See p. 984. differentiation can be made via direct
and musculoskeletal. Transplacental and envi- fluorescent antibody, immunohistochemical
ronmental transmission occurs. Important Interspecies Differences staining of tissue samples, or PCR.
Serologic tests use species-specific reagents and • Almost all commercially available laboratory
Causes of Abnormally High Levels must be adapted for the species of interest. Cats tests for antibody are for immunoglobulin
• Infection with or prior exposure to N. have been experimentally infected, but clinically, G (IgG).
caninum. Rising titer (>4-fold) confirms neosporosis in cats is unknown; natural disease AUTHOR: Sharon M. Dial, DVM, PhD, DACVP
active infection. Positive cerebrospinal fluid in small animals is mainly seen in dogs. N. EDITOR: Lois Roth-Johnson, DVM, PhD, DACVP
titers are suggestive of disease. caninum is an important cause of abortion in
• IFA tests have little cross-reactivity with other ruminants.
parasites, including T. gondii. However, cross-
reactivity depends on the antigen source used Specimen Collection and Handling
for the assay (among other laboratory-based Serum, 1 mL (red top tube), refrigerated
factors) and may vary.

Neutrophils (Neutrophilia, Neutropenia)

Definition Physiology hours before leaving the vascular space for
Granulocytic leukocytes with segmented nuclei Precursors in bone marrow respond to tissues. In blood samples collected for CBC,
and inconspicuous cytoplasmic granules. Their colony-stimulating factors, and produc- only neutrophils in the circulating pool are
primary functions during inflammation are tion is increased during inflammatory and counted.
bacterial phagocytosis and killing. immune responses. Mature neutrophils can
be found in the marrow (storage pool), in Reference Interval
Synonyms peripheral blood (circulation pool), or associ- Dogs: 3-11.5 × 10 neutrophils/mcL; cats:
3
3
Polymorphonuclear neutrophil (PMN), ated with vascular endothelial cells (marginal 2.5-12.5 × 10 neutrophils/mcL
segmented neutrophil pool). Neutrophils circulate for only a few
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