Feline haptoglobin
Harvey, J.W.
American Journal of Veterinary Research 39(4): 549-553
1978
ISSN/ISBN: 0002-9645 PMID: 646191 Document Number: 126617
Hb was injected i.v. in quantities sufficient to bind completely all circulating haptoglobin in 4 cats. Unbound haptoglobin was not in plasma 3 h after injection and all values were below 16 mg/dl for 12 h after injection. Plasma-haptoglobin values from 2 of the cats were within the normal range for cats (31-126 mg/dl) after 24 h and all were within the normal range by 48 h. This rapid synthesis of haptoglobin is of clinical importance because, within 2 days of a transient hemolytic event, haptoglobin values may no longer be sufficiently low to be indicative of intravascular hemolysis. Disappearance of the Hb-haptoglobin complex from plasma was assessed by measuring declining concentrations of plasma Hb with time after i.v. Hb injection. In the range of concentrations of Hb measured in the present study, the disappearance of this complex followed zero-order kinetics, with a mean decrease in plasma Hb of 10.8 mg/dl/hour. Serum haptoglobin was measured in selected cats with experimental and naturally occurring diseases to verify the usefulness of the haptoglobin assay as a diagnostic procedure for intravascular hemolysis. Plasma haptoglobin concentrations also may be useful diagnostically as a nonspecific indicator of tissue injury and inflammation. Plasma-haptoglobin concentrations were increased above normal values in cats following splenectomy and experimentally induced abscesses and in cats with naturally occurring feline infectious peritonitis and upper respiratory tract infection.