Table 3.

NLP approaches used in individual PHI categories at different processing stages

Category	Sub-category	Term Identification			Post-processing
		ML (CRFs)	Rule/Pattern	Keywords	Term Extraction	Trusted PHI
DATE	DATE	✓	✓	✓	✓	✓
NAME	DOCTOR	✓	–	✓	✓	✓
	PATIENT	✓	–	✓	–	✓
	USERNAME	✓	✓	–	–	–
LOCATION	HOSPITAL	✓	–	✓	–	✓
	CITY	✓	–	✓	–	–
	STATE	✓	–	✓	–	–
	STREET	✓	–	✓	–	–
	ZIP	✓	✓	–	–	–
	ORGANIZATION	✓	–	✓	–	–
	COUNTRY	✓	–	✓	–	–
	LOCATION-OTHER	–	–	✓	–	–
AGE	AGE	✓	✓	✓	✓	–
ID	MEDICALRECORD	✓	✓	✓	✓	✓
	IDNUM	✓	✓	✓	–	–
	DEVICE	–	✓	✓	–	–
	BIOID	–	✓	–	–	–
	HEALTHPLAN	–	–	✓	–	–
CONTACT	PHONE	✓	✓	✓	–	✓
	FAX	–	✓	–	–	–
	EMAIL	–	✓	–	–	–
	URL	–	–	✓	–	–
PROFESSION	PROFESSION	✓	–	✓	–	–