Effect of storage of samples at -80 degrees C on the assay of lipoprotein(a) by rate nephelometry (Beckman 360 Array).

The effect of storage of samples on the assay of lipoprotein(a) depends on the technique used. We have tested the automated Beckman 360 Array rate nephelometer using Dako anti-Lp(a) antibody, and an Immunofrance standard and control serum according to the technique of Gillery et al. We found a very high correlation between serum concentrations before freezing and those after three weeks and six months at -80 degrees C. Variations greater than 15% concerned only low levels of Lp(a) and were probably related to the precision of the technique at low concentrations.