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SDMA Semen Analysis 1381

Next Diagnostic Steps to Consider Specimen Collection and Handling • Absence of schistocytes does not rule out
if Levels are High EDTA whole blood (lavender top tube) for • A CBC report of poikilocytosis (a broad term
DIC (correlate with coagulation profile).
VetBooks.ir well as coagulation profile; consider imaging evaluation that refers to the presence of any circulating,
CBC and fresh blood smear for morphologic
Evaluate clinical history and physical exam as
abnormally shaped RBCs) warrants patholo-
studies and infectious disease testing (e.g.,
Relative Cost: $$ (reported as part of CBC)
heartworm, tick-borne disease).
gist review of blood smear to define the shape
change and identify any schistocytes.
Important Interspecies Differences Pearls • Submission of blood smear prepared at time
Schistocytes uncommon in cats with DIC, • Even small numbers of schistocytes are of sample collection will minimize artifacts
possibly because their smaller erythrocytes are clinically significant, indicating underlying of morphology due to specimen age.
less likely to be damaged by fibrin in vascular microangiopathy; unlikely to be induced
spaces. artifactually by smear preparation technique. AUTHOR: Fidelia R. Fernandez, DVM, MS, DACVP
EDITOR: Lois Roth-Johnson, DVM, PhD, DACVP

SDMA

Definition compared to creatinine, which is dependent protein/creatinine ratio, and/or abdominal
A biomarker that aids in the early detection of on muscle mass and is often within reference imaging. See pp. 167 and 169.
renal disease in dogs and cats interval in poorly muscled/cachectic patients
with chronic kidney disease. SDMA is cur- Important Interspecies Differences
Synonym rently offered only by IDEXX Laboratories, Healthy puppies, kittens, and greyhounds may
Symmetric dimethylarginine as an individual test and as part of routine have slightly increased values.
biochemistry panels, and has been added
Physiology to the International Renal Interest Society Specimen Collection and Handling
SDMA is a variant of the amino acid arginine (IRIS) staging guidelines for chronic renal Serum (preferred) or heparinized plasma. Stable
that is produced at a constant rate by all disease. at room temperature for 4 days, longer (14
nucleated cells and is excreted primarily by days) if refrigerated
the kidneys. The molecule is a specific marker Reference Interval
for renal function as it is freely filtered by the Healthy dogs and cats: ≤ 14 mcg/dL Relative Cost: $$ (test performed by
glomerulus, is not reabsorbed by the renal IDEXX Laboratories)
tubules, and correlates well with the glomerular Causes of Abnormally High Levels
filtration rate. SDMA is more sensitive than Renal disease (values > 20 mcg/dL are essentially AUTHOR: Shannon D. Dehghanpir, DVM, MS, DACVP
EDITOR: Lois Roth-Johnson, DVM, PhD, DACVP
creatinine in early detection of chronic kidney diagnostic for renal disease)
disease. An increase in SDMA occurs with
≈40% loss of renal function (versus ≈75% Next Diagnostic Steps to Consider Laboratory Tests
for creatinine). Additionally, unlike creatinine, if Levels are High
SDMA is not influenced by muscle mass. This Assess for renal disease and underlying cause
latter attribute provides a major advantage via urinalysis, serum biochemistry panel, urine

Semen Analysis

Definition number = concentration × volume collected. phosphatase indicates obstruction of genital
Assessment of male ejaculate for volume, sperm Motility, which is often considered an indicator tubular structures.
quantity and morphology, percent of live sperm, of viability, should be ≥ 80%; motility patterns
presence of other cells, bacteria, and, occasion- are random. Sperm should have single heads Next Diagnostic Steps to Consider
ally, alkaline phosphatase. Used primarily as of uniform shape and size; free heads should if Levels are Low
part of assessment of male fertility. Also used be rare; tails are normally straight to slightly Examination of testicle and epididymis on
to assess prostatic disease in intact male dogs. curved. Abnormal sperm have hooked, kinked, physical examination and using ultrasound;
or multiple tails and should be less than 20% measurement of resting plasma testosterone
Physiology of the population. It is common to see a few
Ejaculate is divided into three fractions. First urethral, prostatic, or squamous epithelial cells; Lab Artifacts
and third fractions are mostly prostatic secre- low numbers of bacteria are also common. Aged sample or exposure to temperature
tion; the second sperm-rich fraction should be Alkaline phosphatase > 10,000 U/L. extremes invalidates physical and biochemical
used for evaluation. analysis.
Causes of Abnormally Low Levels
Reference Interval Decreased numbers of normal viable sperm Specimen Collection and Handling
Normal total sperm count is roughly 10 million suggest testicular injury, neoplasia, or atrophy. Motility must be evaluated immediately and
per 1 pound of body weight, where total Decreased concentration of seminal alkaline cannot be assessed in specimens transported

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