Vitamin B12(VB12) CLIA kit (Chemiluminescence Immunoassay) is an in vitro diagnostic quantitative test kit.  A vitamin B12 deficiency can cause fatigue, muscle weakness, intestinal problems, numbness, memory loss and anemia. If left untreated, a B12 deficiency may lead to irreversible nerve damage. Elevated levels of vitamin B12 may indicate health conditions such as liver disease or diabetes.