Development and evaluation of a rapid, semi-automatic micro-method for CH50 estimation using a computer program.

Abstract

Established methods for the estimation of serum complement are often unsatisfactory. Problems include complex mathematical and/or technical manipulations, lack of objectivity, and poor sensitivity. Here we present an assay that is rapid, sensitive, quantitative, simple and semi-automatic by using an 'ELISA' reader to estimate released haemoglobin. It compares very favourable with a more manual, old established method. We have used this new method to establish a normal range, investigate serum storage conditions, and demonstrate that the sensitised sheep red blood cells are suitable targets after overnight storage at 4 degrees C. Furthermore we confirm that serum from patients with systemic lupus erythematosus or Sjögren's syndrome frequently has reduced levels of CH50. Patients with rheumatoid arthritis, scleroderma, Bechet's disease or arteritis have a mean CH50 within the normal range.