HL7 NK1 Segment: Next of Kin

The HL7 NK1 segment (Next of Kin / Associated Parties) carries information about the patient’s emergency contacts, next of kin, legal guardians, and other associated parties. It repeats for multiple contacts and appears primarily in ADT messages — each NK1 representing a different person associated with the patient.

NK1 Field Reference

Seq	Name	Type	Opt	Description
`NK1-1`	Set ID	SI	R	Sequence number (1, 2, 3...)
Reflects contact priority — NK1-1=1 is typically the primary contact.
`★ NK1-2`	Name	XPN	O	Contact person's name
`★ NK1-3`	Relationship	CE	O	SPO, PAR, CHD, GRD, EMC, OTH
How the person is related to the patient. SPO=Spouse, PAR=Parent, CHD=Child, GRD=Guardian, EMC=Emergency Contact, OTH=Other.
`★ NK1-4`	Address	XAD	O	Contact person's address
`★ NK1-5`	Phone Number	XTN	O	Home phone (repeating)
`NK1-6`	Business Phone	XTN	O	Work phone number
`★ NK1-7`	Contact Role	CE	O	EMC, NOK, FED, INS
Functional role: EMC=Emergency Contact, NOK=Next of Kin, GRD=Guardian, POA=Power of Attorney, BIL=Billing Contact. Same person may appear in multiple NK1 segments with different roles.
`NK1-8`	Start Date	DT	O	Relationship effective date
`NK1-9`	End Date	DT	O	Relationship end date
`NK1-10`	Next of Kin Job Title	ST	O	Contact's job title
`NK1-11`	Next of Kin Job Code	JCC	O	Contact's occupation code
`NK1-12`	Employee Number	CX	O	Contact's employee ID
`★ NK1-13`	Organization Name	XON	O	Employer or organization
`NK1-14`	Marital Status	CE	O	Contact's marital status
`NK1-15`	Administrative Sex	IS	O	Contact's sex
`NK1-16`	Date of Birth	TS	O	Contact's date of birth
`NK1-17`	Living Dependency	IS	O	Spouse, small children, etc.
`NK1-18`	Ambulatory Status	IS	O	Mobility status
`NK1-19`	Citizenship	CE	O	Contact's citizenship
`NK1-20`	Primary Language	CE	O	Contact's primary language
`NK1-21`	Living Arrangement	IS	O	Alone, with family, etc.
`NK1-22`	Publicity Code	CE	O	Publicity restrictions
`NK1-23`	Protection Indicator	ID	O	Protected (no information release)
`NK1-24`	Student Indicator	IS	O	Student status
`NK1-25`	Religion	CE	O	Contact's religion
`NK1-26`	Mother's Maiden Name	XPN	O	Mother's maiden name
`NK1-27`	Nationality	CE	O	Contact's nationality
`NK1-28`	Ethnic Group	CE	O	Contact's ethnicity
`NK1-29`	Contact Reason	CE	O	Reason for contact
`NK1-30`	Contact Person Name	XPN	O	Alternate contact name format
`NK1-31`	Contact Person Phone	XTN	O	Alternate phone format
`NK1-32`	Contact Person Address	XAD	O	Alternate address format
`NK1-33`	Associated Party Identifiers	CX	O	Contact's MRN or other IDs

NK1-1 R

Set ID SI

Sequence number (1, 2, 3...)

Reflects contact priority — NK1-1=1 is typically the primary contact.

★ NK1-2 O

Name XPN

Contact person's name

★ NK1-3 O

Relationship CE

SPO, PAR, CHD, GRD, EMC, OTH

How the person is related to the patient. SPO=Spouse, PAR=Parent, CHD=Child, GRD=Guardian, EMC=Emergency Contact, OTH=Other.

★ NK1-4 O

Address XAD

Contact person's address

★ NK1-5 O

Phone Number XTN

Home phone (repeating)

NK1-6 O

Business Phone XTN

Work phone number

★ NK1-7 O

Contact Role CE

EMC, NOK, FED, INS

Functional role: EMC=Emergency Contact, NOK=Next of Kin, GRD=Guardian, POA=Power of Attorney, BIL=Billing Contact. Same person may appear in multiple NK1 segments with different roles.

NK1-8 O

Start Date DT

Relationship effective date

NK1-9 O

End Date DT

Relationship end date

NK1-10 O

Next of Kin Job Title ST

Contact's job title

NK1-11 O

Next of Kin Job Code JCC

Contact's occupation code

NK1-12 O

Employee Number CX

Contact's employee ID

★ NK1-13 O

Organization Name XON

Employer or organization

NK1-14 O

Marital Status CE

Contact's marital status

NK1-15 O

Administrative Sex IS

Contact's sex

NK1-16 O

Date of Birth TS

Contact's date of birth

NK1-17 O

Living Dependency IS

Spouse, small children, etc.

NK1-18 O

Ambulatory Status IS

Mobility status

NK1-19 O

Citizenship CE

Contact's citizenship

NK1-20 O

Primary Language CE

Contact's primary language

NK1-21 O

Living Arrangement IS

Alone, with family, etc.

NK1-22 O

Publicity Code CE

Publicity restrictions

NK1-23 O

Protection Indicator ID

Protected (no information release)

NK1-24 O

Student Indicator IS

Student status

NK1-25 O

Religion CE

Contact's religion

NK1-26 O

Mother's Maiden Name XPN

Mother's maiden name

NK1-27 O

Nationality CE

Contact's nationality

NK1-28 O

Ethnic Group CE

Contact's ethnicity

NK1-29 O

Contact Reason CE

Reason for contact

NK1-30 O

Contact Person Name XPN

Alternate contact name format

NK1-31 O

Contact Person Phone XTN

Alternate phone format

NK1-32 O

Contact Person Address XAD

Alternate address format

NK1-33 O

Associated Party Identifiers CX

Contact's MRN or other IDs

R = Required, O = Optional, C = Conditional, W = Withdrawn (backward compatibility only)

NK1-3: Relationship Codes (HL7 Table 0063)

Code	Relationship	Description
SPO	Spouse	Married partner
DOM	Life Partner	Domestic partner
PAR	Parent	Mother or father
CHD	Child	Son or daughter
GRD	Guardian	Legal guardian
SIB	Sibling	Brother or sister
GRP	Grandparent	Grandmother or grandfather
DEP	Dependent	Dependent of the patient
EMC	Emergency Contact	Designated emergency contact
OWN	Owner	For veterinary or property contexts
NON	None	No relationship specified
OTH	Other	Other relationship not listed
UNK	Unknown	Relationship not determined

NK1-7: Contact Role Codes

Code	Role	Description
EMC	Emergency Contact	Primary emergency notification
NOK	Next of Kin	Legal next of kin
FED	Federal Agency	Government agency contact
INS	Insurance Company	Payer contact
BIL	Billing Contact	Person responsible for billing
GRD	Legal Guardian	Court-appointed guardian
ATT	Attorney	Patient’s legal representative
POA	Power of Attorney	Healthcare/financial POA

NK1-3 (Relationship) describes how the person is related to the patient; NK1-7 (Contact Role) describes their functional role. The same person may appear in multiple NK1 segments with different roles:

NK1|1|DOE^JANE^M|SPO^Spouse^HL70063||^PRN^PH^^^^^555-867-5310||EMC^Emergency Contact^HL70131
NK1|2|DOE^JANE^M|SPO^Spouse^HL70063||^PRN^PH^^^^^555-867-5310||NOK^Next of Kin^HL70131

Sample NK1 Segments

Multiple contacts for a single patient:

NK1|1|DOE^JANE^M|SPO^Spouse^HL70063|123 MAIN ST^^ANYTOWN^OH^44101|^PRN^PH^^^^^555-867-5310||EMC^Emergency Contact^HL70131
NK1|2|DOE^ROBERT^J|PAR^Parent^HL70063|456 OAK AVE^^ANYTOWN^OH^44101|^PRN^PH^^^^^555-867-5320||NOK^Next of Kin^HL70131
NK1|3|SMITH^LISA^A|OTH^Other^HL70063|789 ELM ST^^ANYTOWN^OH^44101|^WPN^PH^^^^^555-555-0200||BIL^Billing Contact^HL70131

NK1|1: Spouse Jane Doe as emergency contact
NK1|2: Father Robert Doe as next of kin
NK1|3: Lisa Smith as billing contact

Key Implementation Considerations

Multiple NK1 Segments and Prioritization

ADT messages may contain 3-5+ NK1 segments. Receiving systems should:

Display all contacts but highlight the primary emergency contact (NK1-7 = EMC)
Respect ordering: NK1-1 (Set ID) typically reflects priority — contact #1 is the primary contact
Filter by role: Some downstream systems only need emergency contacts, while billing systems need NK1-7 = BIL

NK1 vs GT1 (Guarantor)

NK1 and GT1 both carry associated person information but serve different purposes:

Feature	NK1	GT1
Purpose	Emergency contact / next of kin	Financial guarantor (responsible for payment)
Clinical relevance	Yes — who to call in emergencies	No — purely financial
Billing relevance	No	Yes — person responsible for balance
Same person?	Often, but not always	May be a spouse, parent, or the patient

A spouse might appear as both NK1 (emergency contact) and GT1 (guarantor), but they serve different workflows.

HIPAA Considerations

HIPAA regulations affect how NK1 data is used:

Minimum necessary: Only share NK1 information required for the specific purpose (billing contact info doesn’t go to clinical systems)
Patient consent: Some patients may restrict who can receive their health information — check PID consent indicators
Minors: For pediatric patients, NK1 segments identify parents/guardians who have legal authority to receive information and make care decisions
Behavioral health: Patients in psychiatric or substance abuse treatment may have restricted contact lists per 42 CFR Part 2

Emergency Contact Updates

NK1 changes arrive via ADT^A08 (Update Patient Information). When processing A08 messages with NK1:

Full replacement: Most implementations send the complete set of NK1 segments — receiving systems should replace all existing contacts, not merge
Delete detection: If the A08 has fewer NK1 segments than previously stored, removed contacts should be deactivated
Timestamp tracking: Use EVN-6 or MSH-7 to track when contact information was last updated

HL7 ADT Messages ADT message structure — the primary carrier of NK1 segments during registration and patient updates.

PID Segment Reference Patient demographics — NK1 extends PID with associated party information.

HL7 Workbench Parse and validate HL7 messages with segment highlighting and field lookup.

HL7 Resource Center Message types, segments, reference guides, and integration tools.