Tuberculin was invented by Dr. Robert Koch, a German physician and microbiologist, in 1890. **

Tuberculin did not work as a reliable diagnostic tool for tuberculosis because it was found to produce false positive and false negative results. This was due to the fact that tuberculin was a crude mixture of proteins derived from the tuberculosis bacteria, which led to variability in the immune response in different individuals. Additionally, factors such as previous exposure to the tuberculosis bacteria or other mycobacteria could also affect the accuracy of the tuberculin skin test. As a result, more specific and reliable diagnostic tests, such as the interferon-gamma release assays, have been developed to detect tuberculosis infection. **

"Fachkräfte 2" is a German term that translates to "skilled workers 2" in English. It refers to a specific category of skilled workers, typically in the context of labor and employment in Germany. This term is often used in discussions about immigration and workforce development, as Germany has a high demand for skilled workers in various industries. **

The term "Qualifikation" is a German word that translates to "qualification" in English. It refers to the skills, knowledge, and experience that a person possesses in a particular field or area of expertise. Qualifikation is often used in the context of education and employment to describe the level of training and expertise that an individual has acquired. It is an important factor in determining a person's suitability for a job or position. **

"Hobby als Beruf" is a German phrase that translates to "hobby as a profession" in English. It refers to the concept of turning one's hobby or passion into a career or profession. This can involve pursuing a career in a field related to one's hobby, such as becoming a professional musician or artist, or finding a way to monetize and make a living from one's hobby, such as through blogging or creating online content. **

"Tod im Beruf" is a German phrase that translates to "death in the workplace" in English. It refers to the occurrence of a person dying while on the job or as a result of their work-related activities. This term is often used in discussions about workplace safety and the prevention of accidents and fatalities in the workplace. **

"Karriere-Sprung" is a German term that translates to "career jump" in English. It refers to a significant advancement or leap in one's career, such as a promotion, a new job opportunity, or a major career change. **

The correct spelling of Weiterbildung is W-E-I-T-E-R-B-I-L-D-U-N-G. **