How is diagnosis done in TCM?

How is diagnosis done in TCM?   Following the macro philosophy of disease, traditional Chinese diagnostics are based on overall observation of human symptoms rather than "micro" level laboratory tests. There are four types of TCM diagnostic methods: observe (望 wàng), hear and smell (聞 wén), ask about background (問 wèn) and touching (切 qiè).  The pulse-reading component of the touching examination is so important that Chinese patients may refer to going to the doctor as "Going to have my pulse felt" Modern practitioners in China often use a traditional system in combination with Western methods.[citation needed] Traditional Chinese medicine is considered to require considerable diagnostic skill. This often depends on the ability to observe what are described as subtle differences. This may be contrasted with a straightforward laboratory test which indicates an unambiguous cause. A training period of years or decades is said to be necessary for TCM practitioners to understand the full complexity of symptoms and dynamic balances. According to one Chinese saying, A good (TCM) doctor is also qualified to be a good prime minister in a country.