Reversible LDH anomaly appearance by cold storage of serum

Lactate dehydrogenase (LDH) anomaly was observed in cold storage serum of 94 years old female patient. There were an extra band and tailing between LDH 3 and LDH 4 isoenzyme. The immunoprecipitation technique revealed that LDH of this patient was linked to IgG and IgA. However, in the fresh serum, the isoenzyme pattern was normal, and immunoglobulins linked to LDH weren't detected. This anomalous pattern was reduced when a cold storage serum was left for one night at room temperature. Our results indicated that this anomaly was reversible. It had already been reported that LDH anomaly sometimes appeared with cold storage of serum in which there were inhibitory factors to LDH. The present case was characterized by reversible change of LDH anomaly and no reduction of LDH activity.