Test description: Plasma measurement of endogenous ACTH for the diagnosis of adrenal disorders in horses, particularly Cushing’s syndrome/PPID (Pituitary Pars Intermedia Dysfunction).

Notes: It is recommended to collect the sample in the morning and minimize stress, as environmental factors can influence ACTH levels.

• Sample type: EDTA plasma
• Species: Equine
• Recommended volume: 1 mL
• Minimum volume: 0.5 mL
• Container: EDTA tube (purple cap) – without gel separator
• Fasting: 8 a.m. to 12 p.m.
• Rejection criteria: Hemolyzed sample, unrefrigerated sample, or sample submitted as whole blood.

SHIPPING
Follow the step-by-step instructions in our Pocket Guide.
Plasma must be separated immediately after collection and frozen.

• Elevated levels of endogenous ACTH in horses suggest PPID.

• Results should be interpreted taking into account the season (physiologically higher values in the fall), clinical signs, and additional tests.

TEST METHOD
Chemiluminescent Immunoassay (CLIA).

Test description: Measurement of basal serum cortisol levels to assess adrenal function in horses.
Comments: Serum cortisol concentration undergoes circadian variations and is also influenced by stress and medications.

• Sample type: Serum
• Species: Equine
• Recommended volume: 1 mL
• Minimum volume: 0.5 mL
• Container: Tube with a red or yellow cap, without activating gel
• Fasting: 8 a.m. to 12 p.m.
• Rejection criteria: Hemolyzed sample or insufficient volume.

SHIPPING
Follow the step-by-step instructions in our Pocket Guide.
Samples must be refrigerated or frozen until shipment

• Isolated cortisol levels have little diagnostic value.

• The results should be interpreted in conjunction with dynamic tests (e.g., ACTH stimulation or dexamethasone suppression) and the patient’s clinical presentation.

TEST METHOD
Radioimmunoassay (RIA).

Test description: Measurement of basal serum insulin levels in horses.
Comments: Used in the investigation of insulin resistance and as part of the diagnosis of Equine Metabolic Syndrome (EMS).

• Sample type: Serum
• Species: Equine
• Recommended volume: 1 mL
• Minimum volume: 0.5 mL
• Container: Tube with a red or yellow cap, without activating gel
• Fasting: 8 a.m. to 12 p.m.
• Rejection criteria: Hemolyzed or improperly packaged sample.

SHIPPING
Follow the step-by-step instructions in our Pocket Guide.
Samples must be shipped refrigerated or frozen.

• Basal hyperinsulinemia is suggestive of insulin resistance, especially in obese horses or those with recurrent laminitis.

• Results should be correlated with blood glucose levels and, when necessary, with dynamic tests (e.g., oral glucose tolerance test or combined glucose-insulin test).

TEST METHOD
Radioimmunoassay (RIA).

Test description: Serum insulin measurement at two time points (T0 = baseline/fasting and T1 = 2–3 hours postprandial or as specified in the defined dietary protocol).
Comments: Indicated for dynamic assessment of the insulin response in cases of suspected Equine Metabolic Syndrome (EMS) and in horses with recurrent laminitis or obesity.

• Sample: Serum
• Species: Equine
• Optimal volume: 0.7 mL per cycle
• Minimum volume: 0.5 mL per cycle
• Container: Tube with a red or yellow cap, without a gel divider
• Fasting: 8 a.m. to 12 p.m.
• Rejection Criteria: Samples without time stamps (T0/T1), hemolyzed, lipemic, or of insufficient volume

SHIPPING
Clearly identify T0 and T1.

• Excessive postprandial insulin (vs. baseline): suggests insulin resistance/SME.

• Basal and postprandial hyperinsulinemia: increased risk of metabolic disorders and laminitis; consider dietary adjustments and periodic reevaluation.

• Always interpret with blood sugar and, when necessary, with dynamic tests (e.g., oral glucose tolerance test).

TEST METHOD
Radioimmunoassay (RIA).

Test description: Serum progesterone measurement for evaluation luteal in mares.
Comments: Useful for confirming luteal activity (e.g., presence of a corpus luteum), monitor reproductive protocols, and investigate causes of conception failure/early embryonic losses.

• Sample: Serum
• Species: Equine
• Recommended volume: 0.7 mL
• Minimum volume: 0.5 mL
• Container: Tube with a red or yellow cap, without a gel divider
• Fasting: 8 a.m. to 12 p.m.
• Rejection Criteria: Hemolyzed, lipemic, or insufficient-volume samples

• Values consistent with the luteal phase: confirm active luteal function.
• Persistently low concentrations: may indicate luteal insufficiency/absence of the corpus luteum; correlate with ultrasound and reproductive history.
• In protocols for progestin-containing regimens, use for therapeutic monitoring.

TEST METHOD
Chemiluminescent Immunoassay (CLIA).

Test description: Serum testosterone level measurement to assess testicular function in stallions and investigation of cryptorchidism (as a standalone test or as part of stimulation protocols, when requested).
Comments: Assists in the evaluation of reproductive capacity, sexual behavior, and investigations of androgen-secreting testicular tumors.

• Sample: Serum
• Species: Equine
• Recommended volume: 0.7 mL
• Minimum volume: 0.5 mL
• Container: Tube with a red or yellow cap, without a gel divider
• Fasting: 8 a.m. to 12 p.m.
• Rejection Criteria: Hemolyzed, lipemic, or insufficient-volume samples

SHIPPING
Follow the step-by-step instructions in our Pocket Guide.

• Appropriate concentrations in stallions: compatible with testicular function; take seasonal and individual variations into account.

• Low values: may indicate testicular hypofunction; correlate with a semen analysis and andrological examination.

• In suspected cryptorchidism, basal and/or post-stimulation testosterone levels (e.g., hCG, when requested in another protocol) may aid in the diagnosis.

TEST METHOD
Radioimmunoassay (RIA).

Test description: Serum estradiol assay, the primary estrogen produced by the ovaries and adrenal glands.
Comments: Important for assessing reproductive function, diagnosing secretory ovarian tumors (such as granulosa-theca tumors), and monitoring endocrine disorders in mares.

• Sample type: Serum
• Species: Equine
• Recommended volume: 0.7 mL
• Minimum volume: 0.5 mL
• Container: Tube with a red or yellow cap, without activating gel
• Fasting: 8 a.m. to 12 p.m.
• Rejection criteria: Incompatible sample, severe hemolysis, insufficient volume

Elevated levels may be associated with secretory ovarian tumors, while changes in the estrous cycle should be interpreted in conjunction with progesterone levels and ultrasound findings.

Test Method
Radioimmunoassay (RIA).

Test description: Serum quantification of triiodothyronine (T3), an active thyroid hormone derived from the conversion of T4.
Comments: Used as a complementary marker in the evaluation of thyroid function, although abnormalities may reflect non-thyroidal conditions (“low T3 syndrome”).

• Sample type: Serum
• Species: Equine
• Recommended volume: 0.7 mL
• Minimum volume: 0.5 mL
• Container: Tube with a red or yellow cap, without activating gel
• Fasting: 8 a.m. to 12 p.m.
• Rejection criteria: Incompatible sample, severe hemolysis

Low levels may be associated with systemic diseases or medication use; results should be interpreted in conjunction with T4 and TSH.

Test Method
Radioimmunoassay (RIA).

Test description: Serum thyroxine (T4) level, the primary hormone secreted by the thyroid gland.
Comments: Essential for assessing thyroid function, but may be influenced by medications, diet, and non-thyroidal conditions.

• Sample type: Serum
• Species: Equine
• Recommended volume: 0.7 mL
• Minimum volume: 0.5 mL
• Container: Tube with a red or yellow cap, without activating gel
• Fasting: 8 a.m. to 12 p.m.
• Rejection criteria: Incompatible sample, hemolysis, insufficient volume

Low levels do not confirm hypothyroidism in horses; clinical findings and other tests are required.

Test Method
Radioimmunoassay (RIA).

Test description: Quantification of the free fraction of thyroxine (T4), obtained by equilibrium dialysis, which is considered the biologically active form of the hormone.
Comments: Less susceptible to changes in serum proteins and non-thyroidal illnesses compared to Total T4.

• Sample type: Serum
• Species: Equine
• Recommended volume: 0.7 mL
• Minimum volume: 0.5 mL
• Container: Tube with a red or yellow cap, without activating gel
• Fasting: 8 a.m. to 12 p.m.
• Rejection criteria: Hemolyzed sample, insufficient volume, inappropriate tube

Low levels may suggest hypothyroidism, but they should always be interpreted in conjunction with the patient’s medical history, total T4, TSH, and other test results. The equilibrium dialysis method reduces false results associated with systemic diseases.

Test Method
Radioimmunoassay (RIA) after equilibrium dialysis.

Test description: Measurement of thymidine kinase 1 (TK1), an enzyme associated with cell proliferation.
Comments: A supplementary test in the investigation of lymphoma and other proliferative processes in horses, especially when there is clinical suspicion and suggestive imaging findings.

• Sample type: Serum
• Species: Equine
• Recommended volume: 0.7 mL
• Minimum volume: 0.5 mL
• Container: Tube with a red or yellow cap, without activating gel
• Fasting: 8 a.m. to 12 p.m.
• Rejection criteria: Hemolyzed sample, insufficient volume, or improperly packaged

Elevated TK1 levels may indicate proliferative activity associated with lymphoma or neoplasms. The test should be used in conjunction with clinical evaluation, cytology, histopathology, and imaging studies.

Test description: Measurement of serum cortisol levels at baseline (T0) and after ACTH stimulation (T1).

Comments: The primary test for diagnosing hypoadrenocorticism (Addison’s disease) and assessing adrenal reserve in cases of suspected hypercortisolism (Cushing’s syndrome).

• Sample type: Serum
• Species: Canine, Feline, Equine
• Optimal volume: 0.7 mL per cycle
• Minimum volume: 0.5 mL per cycle
• Container: Tube with a red or yellow cap
• Rejection Criteria: Incompatible sample or missing time stamps (T0 and T1)

Send
Follow the step-by-step instructions in our Pocket Guide, clearly identifying the basal (T0) and post-ACTH (T1) tubes.

• Adrenal insufficiency (Addison's disease): Low basal and post-ACTH cortisol levels confirm adrenal reserve insufficiency.

• Hypercortisolism (Cushing's syndrome): Normal dogs may have variable basal cortisol levels, but most dogs with Cushing's disease exhibit an increased post-ACTH response.

* Results should always be evaluated in conjunction with clinical signs, medical history, and additional tests.

Test Method
Radioimmunoassay (RIA).

Test description: Serum measurement of 25-hydroxyvitamin D, the primary metabolite used to assess vitamin D status in dogs and cats.

Comments: Recommended for investigating disorders of calcium and phosphorus metabolism, nutritional assessment, endocrine diseases, and monitoring vitamin supplementation.

• Sample type: Serum

• Species: Canine, Feline, Equine

• Optimal volume: 1.0 mL

• Minimum volume: 0.8 mL

• Container: Tube with a red or yellow cap

• Rejection Criteria: Hemolyzed, lipemic, or insufficient sample volume

Shipping
Follow the step-by-step instructions in our Pocket Guide (link).

• Low values: vitamin D deficiency or insufficiency, associated with chronic kidney disease, unbalanced diets, or gastrointestinal disorders.

• High values: may be related to excessive supplementation or vitamin D toxicity.
  
  Results should be interpreted in conjunction with calcium, phosphorus, and PTH.

Test Method
Mass Spectrometry (LC-MS/MS).

Test description: Serum cobalamin (vitamin B12) level, essential for cellular metabolism and intestinal mucosal integrity.

Comments: Indicated for the evaluation of intestinal malabsorption, exocrine pancreatic insufficiency (EPI), and chronic enteropathies.

• Sample type: Serum
• Species: Canine, Feline, Equine
• Recommended volume: 0.7 mL
• Minimum volume: 0.5 mL
• Container: Tube with a red or yellow cap
• Rejection Criteria: Hemolyzed, lipemic, or insufficient sample volume

• Low values: consistent with ileal malabsorption, chronic enteropathies, or IPE.
• Elevated levels: may occur with supplementation, liver disease, or neoplasms.
  

* Vitamin B12 deficiency is associated with chronic diarrhea, weight loss, and stunted growth.

Test Method
Chemiluminescent Immunoassay (CLIA).

Test description: Serum measurement of folic acid, which is absorbed primarily in the proximal small intestine.

Comments: Helps assess intestinal absorption and differentiate between types of enteropathy.

• Sample type: Serum

• Species: Canine, Feline, Equine

• Recommended volume: 0.7 mL

• Minimum volume: 0.5 mL

• Container: Tube with a red or yellow cap

• Rejection Criteria: Hemolyzed, lipemic, or insufficient sample volume

• Low values: may indicate a disease of the proximal intestine.

• High values: may occur in cases of excessive bacterial overgrowth (SIBO).

* The results should be interpreted in conjunction with vitamin B12 levels.

Test Method
Chemiluminescent Immunoassay (CLIA).

• Sample type: Serum
• Species: Canine, Feline, and Equine
• Optimal volume: 1.0 mL
• Minimum volume: 0.5 mL
• Shipping container: Tube with a red or yellow cap
• Rejection Criteria: Hemolyzed or lipemic samples, or samples with insufficient volume

Test description: Serum Vitamin E (alpha-tocopherol) measurement to assess the patient’s antioxidant and nutritional status.

Comments: Recommended for the investigation of neuromuscular disorders, inflammatory diseases, intestinal malabsorption syndromes, and conditions associated with oxidative stress.

Low levels may be related to liver, pancreatic, or intestinal diseases, while high levels are generally associated with supplementation.

• Sample type: Serum
• Species: Canine, Feline, Equine
• Recommended volume: 0.7 mL
• Minimum volume: 0.5 mL
• Container: Tube with a red or yellow cap
• Rejection Criteria: Severe hemolysis, marked lipemia, prolonged exposure to light, or insufficient volume
  

Important note:
The sample must be protected from light and kept refrigerated until shipment.

Test description: Serum aspartate aminotransferase (AST) level, an enzyme found primarily in the liver and skeletal muscle.

Comments: Indicated for the investigation of hepatocellular and muscle damage. AST is not specific to the liver and should be interpreted in conjunction with ALT, FA, and, when muscle injury is suspected, with CK.

• Sample type: Serum
• Species: Canine, Feline, Equine
• Recommended volume: 1 mL
• Minimum volume: 0.5 mL
• Container: Tube with a red or yellow cap
• Rejection Criteria: Hemolyzed sample (may cause significant interference), severely lipemic sample, or insufficient volume

Test description: Serum gamma-glutamyl transferase (GGT) assay, an enzyme primarily associated with the biliary epithelium.

Comments: Indicated for the investigation of cholestasis, hepatobiliary diseases, and monitoring of liver abnormalities. In horses, it is considered a sensitive marker for hepatobiliary disorders, especially cholestatic ones.

• Sample type: Serum
• Species: Canine, Feline, Equine
• Recommended volume: 0.5 mL
• Minimum volume: 0.5 mL
• Container: Tube with a red or yellow cap
• Rejection Criteria: Severe hemolysis, marked lipemia, or insufficient volume

Test description: Serum or plasma total protein measurement, which corresponds to the sum of the circulating albumin and globulin fractions.

Comments: Indicated for assessing nutritional, inflammatory, hepatic, and renal status. It can aid in the investigation of dehydration, chronic inflammatory diseases, immune-mediated diseases, liver diseases, and protein loss (renal or gastrointestinal).

• Sample type: Serum or plasma
• Species: Canine, Feline, Equine
• Recommended volume: 1 mL
• Minimum volume: 0.5 mL
• Container: Tube with a red or yellow cap (for serum)
• Rejection Criteria: Severe hemolysis, marked lipemia, or insufficient volume

Test description: Serum or plasma sodium measurement, the primary extracellular cation, essential for fluid and electrolyte balance and neuromuscular function.

Comments: Indicated for the evaluation of electrolyte disturbances, acid-base imbalances, renal and adrenal disorders (such as hypoadrenocorticism), and critically ill patients. Changes in sodium levels can directly impact the patient’s neurological status.

• Sample type: Serum
• Species: Canine, Feline, Equine
• Recommended volume: 1 mL
• Minimum volume: 0.5 mL
• Container: Tube with a yellow or red cap
• Rejection Criteria: Severe hemolysis or insufficient volume

Hyponatremia: It may be associated with hypoadrenocorticism, renal failure, gastrointestinal fluid loss, or excessive fluid therapy.

Hypernatremia: It can occur in cases of dehydration, diabetes insipidus, or excessive fluid loss.

* The interpretation should take into account potassium, chloride, and the patient's clinical condition.

Test description: Serum or plasma potassium measurement, the primary intracellular cation, essential for neuromuscular and cardiac function.

Comments: Indicated for the investigation of electrolyte disturbances, renal and adrenal disorders (especially hypoadrenocorticism), metabolic acidosis, and critically ill patients. Significant abnormalities may cause potentially serious cardiac arrhythmias.

• Sample type: Serum
• Species: Canine, Feline, Equine
• Recommended volume: 1 mL
• Minimum volume: 0.5 mL
• Container: Tube with a yellow or red cap
• Rejection Criteria: Hemolyzed sample (may falsely elevate the result), insufficient volume

Hypokalemia: May occur in cases of gastrointestinal fluid loss, diuretic use, chronic kidney disease, or prolonged anorexia (especially in cats).

Hyperkalemia: May be associated with hypoadrenocorticism, acute renal failure, urinary obstruction, or hemolysis of the sample.

* The interpretation should take into account sodium, chloride, and the Na:K ratio, where applicable.

Test description: Serum measurement of creatine kinase (CK), an enzyme found primarily in skeletal and cardiac muscle and, to a lesser extent, in brain tissue.

Comments: Indicated for the investigation of acute muscle injuries, myopathies, trauma, seizures, rhabdomyolysis, and the monitoring of muscle diseases.

In horses, it is widely used to assess exercise-induced myopathies and muscle injuries. CK is considered a sensitive marker of recent muscle injury, showing a rapid increase following tissue damage.

• Sample type: Serum
• Species: Canine, Feline, Equine
• Recommended volume: 1 mL
• Minimum volume: 0.5 mL
• Container: Tube with a red or yellow cap
• Rejection Criteria: Severe hemolysis or insufficient volume

Important note:
CK levels may rise temporarily after intense exercise, vigorous straining, or intramuscular injection.

Test description: Serum measurement of total bilirubin and its fractions (direct and indirect), a pigment derived from the breakdown of hemoglobin.

Comments: Indicated for the investigation of jaundice, hemolysis, liver diseases, and biliary disorders.

Assessment of these fractions helps distinguish between prehepatic (hemolysis), hepatic (hepatocellular injury), and posthepatic (cholestasis/biliary obstruction) causes. In horses, mild elevations may occur during prolonged fasting.

• Sample type: Serum
• Species: Canine, Feline, Equine
• Recommended volume: 1 mL
• Minimum volume: 0.5 mL
• Container: Tube with a red or yellow cap
• Rejection Criteria: Severe hemolysis, marked lipemia, or insufficient volume

Important note:
The sample must be protected from light to prevent degradation of bilirubin.

Test description: Serum triglyceride measurement, the primary form of lipid storage in the body.

Comments: Indicated for the investigation of dyslipidemia, pancreatitis, endocrine disorders (such as diabetes mellitus, hypothyroidism, and hyperadrenocorticism), and metabolic monitoring.

It may be significantly affected by improper fasting.

• Sample type: Serum
• Species: Canine, Feline, Equine
• Recommended volume: 1 mL
• Minimum volume: 0.5 mL
• Container: Tube with a red or yellow cap
• Rejection Criteria: Sample with high lipid content, hemolyzed, or insufficient volume

Important note:
A 12-hour fast is recommended for more accurate results.

High values:

• They may indicate primary or secondary dyslipidemia (diabetes mellitus, hypothyroidism, hyperadrenocorticism).
• They may be associated with an increased risk of pancreatitis in dogs.

Reduced prices:

• Generally of no significant clinical relevance on its own.

* The interpretation should take into account the patient's cholesterol levels, blood glucose levels, and clinical presentation