• Include these codes as defined in http://terminology.hl7.org/CodeSystem/v3-ActClass version 3.1.1

  Code	Display	Definition
  OBSSER	observation series	Container for Correlated Observation Sequences sharing a common frame of reference. All Observations of the same cd must be comparable and relative to the common frame of reference. For example, a 3-channel ECG device records a 12-lead ECG in 4 steps (3 leads at a time). Each of the separate 3-channel recordings would be in their own "OBSCOR". And, all 4 OBSCOR would be contained in one OBSSER because all the times are relative to the same origin (beginning of the recording) and all the ECG signals were from a fixed set of electrodes.
  OBSCOR	correlated observation sequences	Container for Observation Sequences (Observations whose values are contained in LIST<>'s) having values correlated with each other. Each contained Observation Sequence LIST<> must be the same length. Values in the LIST<>'s are correlated based on index. E.g. the values in position 2 in all the LIST<>'s are correlated. This is analogous to a table where each column is an Observation Sequence with a LIST<> of values, and each row in the table is a correlation between the columns. For example, a 12-lead ECG would contain 13 sequences: one sequence for time, and a sequence for each of the 12 leads.

This value set expansion contains 2 concepts.