The Pregnancy lab has blogged previously about false negative results in qualitative point-of-care (POC) hCG devices due to high concentrations of hCGβcf in urine. It is shown that the majority of qualitative POC hCG devices are actually susceptible to false negative results due to saturation of capture antibodies by high concentrations of hCGβcf. These findings have led to an increased interest in urine hCGβcf measurements.
However, only a few research laboratories quantify hCGβcf, so it is difficult for most clinical laboratories to determine which urine samples have high concentrations of this hCG variant.
An Easy Way to Estimate hCGβcf Concentration in Urine