What is the difference between the EQ-5D descriptive system, the EQ VAS and the EQ-5D index values?

The descriptive system section of the EQ-5D questionnaire produces a 5-digit health state profile that represents the level of reported problems on each of the five dimensions of health, e.g.EQ-5D-5L health state 21143 represents a patient who indicates slight problems on the mobility dimension, no problems on the self-care and usual activities dimensions, severe pain or discomfort and moderate problems on the anxiety/depression dimension. These health states can be converted into a single index value using one of the standard EQ-5D-5L value sets. These value sets reflect the preferences of the general population. In contrast, the EQ VAS scores are self-reported and are therefore not representative of the general population. The EQ VAS self-rating records the respondent’s own assessment of their health status. Furthermore, the EQ VAS scores are anchored on 100 = the best health you can imagine and 0 = the worst health you can imagine, whereas the value sets are anchored on 11111 = 1 (representing full health) and dead = 0 and can therefore be used in QALY calculations.