In 2016 the CalproSmart rapid test for clinic and home use was launched. The CalproSmart^® kit is validated and approved for self-testing, and is used for monitoring IBD treatment using a SMART phone, trending the quantitative levels of Calprotectin, and improving patient quality of life.

In 2000 an improved assay was developed by Tøn et al. Whereas the initial cut off value for fecal calprotectin between normal and patients with organic bowel disease was 10 mg/kg, it was now increased to 50 mg/kg, which is still recommended for the Calpro kits. Samples with high calprotectin values were increased to a slightly higher degree than low calprotectin samples, thus improving the separation between high and low calprotectin levels.

In the 20^th century there was no commercial test kit available except Nycomed ELISA based on Calpro technology, but after standardized extraction methods had been developed and some gastroenterologists described  faecal calprotectin as a promising noninvasive marker to differentiate IBD from IBS, the interest “exploded”  around 2000.  Up to now more than 2000 studies on calprotectin are published in peer review journals. Several issues regarding the use of fecal calprotectin testing in clinical medicine are discussed, included methodological and economic aspects. 

Calpro AS was established in 1993, and based on the technology of Calpro the first commercial ELISA kit, Nycomed ELISA, for determination of calprotectin in faeces was launched in 1994. A patented buffer for extraction of calprotectin from feces, which had been developed by Calpro, was included in the test kit.

In 1991 Inge Dale did his doctoral thesis on these studies. During the first half of the nineties 3 Scandinavian ph.d.’s were published; all based on the original quantitative technology, using our purified calprotectin and polyclonal antibodies.

Quantitative methods for assessment of calprotectin in blood and tissues were established in 1984, including an ELISA, and during the eighties immunohistochemical studies were performed by Inge Dale, showing that the protein is abundantly found in neutrophil granulocytes, counting for 60 % of the proteins in the cytoplasm. Blood monocytes, like tissue macrophages, which are monocytes that have passed through the walls of vessels and migrated into the tissues, are also calprotectin positive. In addition, squamous epithelium of internal organs (esophaguis, mouth, vagina), and the cells of squamous cell carcinoma are also calprotectin positive.

In 1983 the study “Purification and Partial Characterization of a Highly Immunogenic Human Leucocyte Protein, the L1 Antigen”  was published. Further investigations showed that each molecule binds 6 Ca-atoms, and as purified protein also inhibits the growth of certain bacteria in vitro, we renamed the protein “Calprotectin”.

Back in 1980 Inge Dale and Magne K. Fagerhol immunized rabbits with fractionated samples of leukocytes; among many antibodies one differed  markedly from the others, forming distinct immunoprecipitates in gel containing Ca++-ions.