As an AI language model, I do not have personal experiences or opinions. However, I can provide some general information that might be helpful.

Serum Glypican-3 (GPC3) is a protein that has been investigated as a potential biomarker for certain types of cancer. Cusabio ELISA kits are one of the commercially available kits used to measure GPC3 levels in serum samples. These kits use a sandwich enzyme-linked immunosorbent assay (ELISA) format, where the GPC3 in the sample is captured by a specific antibody and then detected by a secondary antibody that is conjugated with an enzyme. The amount of enzyme activity is then measured and is proportional to the amount of GPC3 in the sample.

There can be several factors that may affect the performance of the ELISA kit, including the quality of the antibodies used in the kit, the specificity and sensitivity of the assay, and the composition of the sample being tested. Sometimes, factors such as sample preparation, storage, and handling can also affect the results. It is important to follow the manufacturer's instructions for the kit and validate the assay in your laboratory before using it for analysis.

In your case, the low absorbance values and the high percentage of results below the lower limit of quantification (LLOQ) and above the upper limit of quantification (ULOQ) suggest that there may be issues with the assay performance. It is possible that there was a problem with the kit or the assay conditions, or the samples may have interfered with the assay. It may be useful to run additional controls and troubleshoot the assay to determine the source of the problem. If you continue to have issues with the kit, you may want to contact the manufacturer for assistance or consider trying a different kit or assay method.