Reference intervals for serum amyloid A, haptoglobin, ceruloplasmin, and fibrinogen in apparently healthy neonatal lambs.

BACKGROUND Acute-phase proteins (APPs) are considered biomarkers for diagnoses, prognoses, and treatment and health status monitoring. Reference intervals (RIs) are an integral part of diagnostic laboratory testing and clinical decision-making. The RIs for neonatal lambs are lacking. OBJECTIVE This study aimed to determine the RIs of serum amyloid A (SAA), haptoglobin (Hp), ceruloplasmin (Cp), and fibrinogen (Fb) concentrations in neonatal cross-bred Kivircik lambs. METHODS The study consisted of 42 neonatal cross-bred Kivircik lambs. Physical examinations were performed daily, and blood samples were collected at 0 (precolostrum), 1, 3, 7, 14, 21, and 28 days of age. The RIs of SAA, Hp, Cp, and Fb concentrations were calculated according to the recommendation of the American Society for Veterinary Clinical Pathology. Results were also evaluated for age- and sex-related effects. RESULTS The RI for serum Hp was 0-0.4 g/L, and no apparent effect of age or sex was noted. Because of significant age- and sex-related differences, the SAA (0.34-55.12 µg/mL), Cp (2.4-26.07 mg/mL), and Fb (218.86-527.82 mg/mL) results were given as minimum and maximum values. Serum SAA on the 1st, 3rd, and 7th days of life, and Cp and Fb concentrations on the 14th and 21st days of life, were significantly higher than those on other study days. CONCLUSIONS This study is the first to establish RIs for neonatal lambs, and the values obtained could be useful for making clinical decisions regarding cross-bred Kivircik lambs during this critical period.