Tests Available and Summary
Iron and TIBC | Ferritin Assay | Non-heme Iron | Haptoglobin | Ceruloplasmin | Feline Blood Card Typing | Canine Blood Card Typing for DEA 1.1 | Alpha-mannosidase
Iron and TIBC
Iron in the body is a necessary metal required not only for the synthesis of hemoglobin but also for many cellular enzymes and coenzymes. Iron is transported in serum bound to the protein transferrin. Normally, only about one-third of the available binding sites on transferrin are occupied by iron. The total iron binding capacity is found in serum; therefore, it includes the amount of iron already bound to the transferrin (serum iron) plus the amount of iron required to saturate the unoccupied binding sites of transferrin. Clinically the determination of serum iron and total iron binding capacity is useful in the differential diagnosis of anemias and other iron disorders.
The spectrophotometric measurement of serum iron is accomplished by releasing the protein bound iron from its carrier protein transferrin and complexing the released iron with a suitable chromogen. In our method, the serum sample from any species is added to an acidic buffered reagent containing hydroxylamine, thiourea and Ferene.
Ferritin Assay
Ferritin is the iron-apoferritin complex, which is one of the chief forms in which iron is stored in the body. In general, ferritin occurs in the gastrointestinal mucosa, liver, spleen, bone marrow, and reticuloendothelial cells.
This procedure is an enzyme-linked immunoabsorptive assay (ELISA) which measures serum ferritin by the sandwich technique. Serum ferritin is used to estimate the total body stores of iron. Values can also be increased with infections, cancer, and other acute phase reactions. The ferritin assay is species specific. At this time, we are limited to the ferritin assay for dog, cat, horse, rhino, tapir, primate/lemur, fur seal, and dolphin.
Non-heme Iron
Non-heme iron is iron not bound within a porphyrin ring.
This procedure measures tissue iron that is not bound to any heme containing compounds. It is used to determine body iron stores for diagnosing iron deficiencies or iron overload.
Haptoglobin
Haptoglobin is a plasma glycoprotein that binds αβ-dimers of free hemoglobin. Its concentration in plasma differs in healthy individuals of various species and can change during disease. Most species have haptoglobin levels in the range of 100-300 mg/dL, but some species (i.e. cattle and pigs) normally have low plasma haptoglobin concentrations. Haptoglobin concentration decreases when free hemoglobin appears in plasma. That happens because haptoglobin-hemoglobin complexes are removed by the liver faster than haptoglobin can be synthesized. Haptoglobin synthesis increases during acute infection and inflammation as part of the acute phase reaction. Thus, serum haptoglobin concentration can be used to monitor the acute phase response. It is particularly valuable in those species that normally have low haptoglobin levels.
This method depends on the peroxidatic activity of hemoglobin and was adapted from the assay of Makimura and Suzuki. When hemoglobin is added in excess to serum samples, it binds to haptoglobin and becomes resistant to acid inactivation. In contrast, the peroxidatic activity of free hemoglobin is lost. The haptoglobin concentration is calculated with a standard curve prepared by incubating known amounts of hemoglobin with a serum sample containing a haptoglobin concentration greater than 150 mg/dL.
Ceruloplasmin
Ceruloplasmin is an “acute reactive” protein and its concentration in serum is moderately increased (50 to 100 percent) in conditions of physiological stress. Increased levels of the protein are encountered in acute infections, in chronic conditions such as rheumatoid arthritis, lupus, and cirrhosis, after myocardial infarctions, (tissue necrosis), and after stress of surgery. Somewhat greater elevations (up to two-fold) are observed in hepatitis, Hodgkins disease, metastatic carcinoma, and hyperthyroidism. Diminished levels of the enzyme are encountered in several conditions: nutritional protein deficiency (malabsorption as well as malnutrition), severe liver disease, and nephrosis. About 94 to 95 percent of the total copper in plasma is present in the ceruloplasmin molecule, and the remainder is bound to albumin; only a trace is present as free Cu2+. By virtue of its copper content, ceruloplasmin is an important vehicle for transport of copper in the body.
This method depends on the oxidative activity of p-phenylenediamine. When this substrate is combined with serum, it produces a purple-colored compound and is read colorometrically.
Feline Blood Card Typing
Cat blood typing is used to determine the cat’s specific blood type before a transfusion. An animal is transfused with type specific blood to prevent a transfusion reaction. Transfusion reactions can cause serious illness or death. Cats have three blood types (A, B, and AB). Most cats (>99%) are blood type A. Type B cats have a natural occurring antibody to blood type A. Some purebred breeds have a high incidence of blood type B (17-59%). When cats with type B are transfused with type A RBCs, an acute transfusion reaction can occur.
This procedure is performed on a specially designed blood typing card manufactured exclusively in our laboratory. Presence or absence of agglutination in the test wells of the card determine blood type, A, B, or AB.
Canine Blood Card Typing for DEA 1.1
Dog blood typing is used to determine the dog’s specific blood type before a transfusion. An animal is transfused with type specific blood to prevent a transfusion reaction. Transfusion reactions can cause serious illness or death. Dogs have at least 7 blood types. Blood types DEA (dog erythrocyte antigen) 1.1 and 1.2 are the most immunogenic and when transfused into a dog without those blood types will alloimmunize the transfused dog. Some dogs have a naturally occurring antibody to blood type 7. The “universal donor” should be negative for blood types 1.1, 1.2, and 7 and negative for antibody to blood type 7.
This procedure is performed on a specially designed blood typing card manufactured exclusively in our laboratory. Presence or absence of agglutination in the test wells of the card determine blood type DEA 1.1 positive or negative.
Alpha-mannosidase
A disease of Angus cattle previously known as pseudolipidosis has been shown to be an inherited lysosomal storage disease, in which an oligosaccharide containing mannose and glucosamine is the storage substance. Diseased animals have a near-absolute deficiency of the lysosomal enzyme, α-mannosidase, whereas heterozygotes have a partial deficiency of this enzyme. The condition is analogous to the human disease known as mannosidosis. A disease of angus cattle characterized by head tremor, an aggressive tendency, ataxia, incoordination, failure to thrive and premature death, was described in Australia by Whittem & Walker (1957). It has since been diagnosed on numerous occasions in that country and New Zealand (various personal communications). Pathologically there is vacuolation of neurons and reticulo-endothelial cells within lymph nodes. Recognizing a similarity to the lipidoses of children, but unable to demonstrate stored lipid, Whittem & Walker, (1957) introduced the name ‘pseudolipidosis.’ Recent work has confirmed and augmented the initial description of this disease (Jolly, 1970, 1971). It may be clinically present at birth, though more commonly it is not noted for several weeks or months. Affected animals fail to thrive, show progressive development of nervous signs and die, usually within the first 12 months of life.
This test measures the concentration of the enzyme alpha mannosidase in plasma by measuring the rate of liberation of 4-methylumbelliferone from the substrate 4-methylumbelliferyl-α-D-mannopyranoside. The fluorescence of 4-methylumbelliferone is measured in a fluorometer by using 0-52 and 7-37 primary filters and a 3-73 secondary filter. Dilutions of 4-methylumbelliferone in a glycine buffer are used as standards.