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Effects of storage on serum ionized calcium and pH from horses with normal and abnormal ionized calcium

Patricia A. Schenck1, Dennis J. Chew, Charles L. Brooks

  • 1Buckeye Feed Mills, Inc., P.O. Box 505, 330 East Schultz Avenue, Dalton, OH 44618.

Veterinary Clinical Pathology
|January 1, 1996
PubMed

Insights

Equine serum ionized calcium (Ca(I)) is stable for 7 days when refrigerated or frozen. However, pH measurements are only accurate for 3 days refrigerated or 1 day frozen, regardless of horse health.

Area of Science:

  • Veterinary Clinical Chemistry
  • Equine Serum Analysis

Background:

  • Previous studies indicated stable ionized calcium (Ca(I)) in healthy horse serum at 40°C for 10 days.
  • The stability of Ca(I) and pH in horses with abnormal Ca(I) concentrations was not previously established.

Purpose of the Study:

  • To evaluate the stability of ionized calcium (Ca(I)) concentration and pH in equine serum.
  • To assess the impact of storage duration (various times) and temperature (40°C and -10°C) on serum Ca(I) and pH.
  • To determine stability in horses with both normal and abnormal Ca(I) concentrations.

Main Methods:

  • Equine serum samples from horses with normal and abnormal Ca(I) concentrations were collected.
  • Serum was stored at 40°C and -10°C for various durations.
  • Ionized calcium (Ca(I)) concentration and pH were measured at different time points.

Main Results:

  • Serum Ca(I) concentration remained stable for 7 days under both cold (40°C) and frozen (-10°C) storage.
  • A significant decrease in serum Ca(I) was observed after 14 days of frozen storage.
  • Serum pH significantly increased after 7 days of cold storage and within 3 days of frozen storage.

Conclusions:

  • Equine serum Ca(I) can be accurately measured for approximately 7 days post-collection if stored anaerobically, cold, or frozen, irrespective of the animal's health status.
  • Accurate equine serum pH measurements are feasible within 3 days of cold storage or 1 day of frozen storage.

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