Page 2634 - Cote clinical veterinary advisor dogs and cats 4th

1344 Folate

pressure, or impaired lymphatic drainage. • Exudate: inflammation (e.g., pancreatitis), ○ Neoplasia: immunocytochemistry can
Mechanistic classification of effusions based infection (e.g., bacterial peritonitis), neoplasia help categorize carcinoma, mesothelioma,
VetBooks.ir viscus leakage helps limit the list of differential splenic rupture), lymphatic disease. Typically ○ Uroperitoneum: measure fluid creatinine
(e.g., mesothelioma), hemorrhage (e.g.,
lymphoma, etc.
on either transudation, exudation, or vessel/
turbid and white to brown
(> 2× plasma creatinine).
diagnoses and is based on the total protein
(TP) quantification, total nucleated cell counts
(> 2× plasma bilirubin).
TP:
(TNCC) and red blood cell (RBC) counts, and • Specific effusions with variable TNCC and ○ Bile peritonitis: measure fluid bilirubin
physical and chemical evaluation. ○ Feline infectious peritonitis: low TNCC
(<3000 cells/mcL) with markedly high TP Specimen Collection and Handling
Reference Interval (>4.5 g/dL). Typically clear and yellow Submit fluid in EDTA (preferable) and red top
• Normal: TNCC < 3000 cells/mcL and TP ○ Hemorrhage: high RBC; TNCC is tube. Submit direct smears prepared at time of
< 2.5 g/dL. Scant in amount comparable to blood. Typically red and sample collection.
• Transudate: TNCC < 3000 cells/mcL and does not clot
TP < 2.5 g/dL ○ Chylous effusion/lymphorrhage: Small Relative Cost: $$
• Protein-enriched (“modified”) transudate: lymphocytes predominate +/- increased
TNCC < 3000 cells/mcL and TP ≥ 2.5 g/ neutrophils and lipid-laden macrophages Pearls
dL if chronic. Typically white • Malodorous fluid or fluid containing
• Exudate: TNCC > 3000 cells/mcL and TP ○ Neoplasia (e.g., carcinoma, mesothelioma, degenerate neutrophils +/- bacteria should
typically > 2.5 g/dL (unless hypoalbumin- lymphoma); variable appearance be submitted for culture.
emia is present). The character of exudate ○ Uroperitoneum; may have concurrent • Though often white, chylous effusion may
varies more than transudate or modified hemorrhage be clear in anorexic animals.
transudate, depending on cause. ○ Bile peritonitis; typically yellow to green • Though often yellow/brown, effusion from a
biliary tract rupture can be clear (i.e., white
Causes of Abnormally High Levels Next Diagnostic Steps to Consider bile).
• Transudate: hypoalbuminemia, pre-sinusoidal if Levels are High • Very small amounts of bleeding can cause a
hypertension. Typically clear and colorless • Ancillary biochemical analysis: pink or red effusion due to a nonhemorrhagic
• Protein-enriched (“modified”) transudate: ○ Chylous effusion/lymphorrhage: measure cause.
heart failure, post-sinusoidal hypertension. fluid triglycerides to determine if chylous
Typically clear and amber (> 100 mg/dL) AUTHOR: Shannon D. Dehghanpir, DVM, MS, DACVP
EDITOR: Lois Roth-Johnson, DVM, PhD, DACVP

Folate

Definition measurement. Check history for dietary Specimen Collection and Handling
Anionic form of folic acid supplementation. Serum (red top tube). Fast animal and separate
serum from clot as soon as possible to avoid
Synonyms Causes of Abnormally Low Levels hemolysis. Store frozen (preferred) or refrigerate
Folic acid, vitamin B 9 Small intestinal mucosal disease, antibiotics up to 48 hours only.
depleting intestinal flora, rarely dietary defi-
Physiology ciency, possibly extensive neoplasia (as folate Relative Cost: $ (folate); $$$ (folate,
Primary source is diet; also produced by enteric is used in DNA synthesis) cobalamin, trypsin-like immunoreactivity)
bacteria. Ingested folate is released from food
and hydrolyzed in proximal small intestine. Next Diagnostic Steps to Consider Pearls
Dietary and bacterial origin folate is taken up if Levels are Low • Evaluate folate in conjunction with cobala-
by proximal intestinal epithelium, metabolized, Rule out artifact due to sample light exposure. min and TLI. Reference laboratories typically
and absorbed into blood. Evaluate diet, medication history. Assess for offer panels that include all three tests.
inflammatory or other bowel diseases. Assess • Cobalamin deficiency may cause normal
Reference Interval for EPI with TLI measurement. or increased folate concentrations (it may
Dogs: 7.7-24.4 mcg/L; cats: 9.7-21.6 mcg/L. accumulate when cobalamin is unavailable
Unit conversion: mcg/L × 2.226 = nmol/L. Important Interspecies Differences to act with it as a cofactor).
Increased folate (due to bacterial overgrowth) • Dietary deficiency is uncommon as folate is
Causes of Abnormally High Levels associated with low IgA in German shepherd dogs. abundant in commercial pet foods.
Small intestinal bacterial overgrowth (intestinal • Although high levels may be seen, assessment
dysbiosis) with/without exocrine pancreatic Drug Effects of folate levels is no longer considered reliable
insufficiency (EPI), impaired gastric acid secre- Antibiotics depleting intestinal flora could for the diagnosis of bacterial overgrowth/
tion, low intestinal pH due to EPI or excessive decrease levels. Phenytoin and sulfasalazine dysbiosis.
gastric acid production, oversupplementation, can decrease levels in humans; unconfirmed • Human maternal folate deficiency is
cobalamin deficiency in animals. associated with congenital malformations,
but there is no evidence of this in dogs and
Next Diagnostic Steps to Consider Lab Artifacts cats.
if Levels are High • False increase: hemolyzed specimens (released
Rule out sample hemolysis. Test for EPI from erythrocytes) AUTHOR: Shelley Burton, DVM, MSc, DACVP
EDITOR: Lois Roth-Johnson, DVM, PhD, DACVP
with trypsin-like immunoreactivity (TLI) • Falsely decreased: excessive light exposure
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