The first activity in a referral to treatment period:
10 - First activity
11 - End of active monitoring
12 - Consultant referral

Subsequent activity during a referral to treatment period:
20 - subsequent activity. Further activities anticipated
21 - Transfer to another healthcare provider

Activity that ends a referral to treatment period:
30 - First treatment - the start of the first treatment that's intended to manage a patient's disease, condition or injury.
31 - Start of active monitoring, initiated by the patient
32 - Start of active monitoring, initiated by the care professional
33 - Failure to attend the first care activity after referral
34 - Decision not to treat or not further contact required
35 - Patient decline offered treatment
36 - Patient died before treatment

Activity that is not part of a referral to treatment period:
90 - After treatment - first treatment occurred previously, eg admitted as an emergency from A&E;
91 - Active monitoring (the patient is observed but not treated)
92 - Not yet referred
98 - Not applicable

Activity where the referral to treatment period status is not yet known:
99 - Not yet known