Crp 0.4 but hs-crp showing 8.5 in the same week. Any explanation? Can spondylitis or lupus cause monoclonal light chain in urine lambda type? K/l 1.5

Many issues. CRP is measured in mg/dL and hsCRP is measured in mg/L. if the later is converted to CRP, the two values would be 0.4 and 0.8 and that is not that great a difference. K/L ratio of 1.5 is normal. The autoimmune disorders you mentioned may have an oligoclonal pattern and could result in monoclonal lambda chain in urine, without there being any cancer. About 10% of people your age have a benign monoclonal gammopathy.