add dosage sequence constraints #263

input/fsh/invariants/ch-dosage.fsh

@@ -0,0 +1,49 @@
+// Base - Dosage.sequence
+Invariant: ch-dosage-1
+Description: "No sequence number (for one dosage element) or sequence number = 1 (for more than one dosage element)"
+Severity: #error
+Expression: "$this.count() = 0 or $this = 1"
+
+// Split - Dosage.sequence
+Invariant: ch-dosage-2
+Description: "The sequence number must be greater than 1"
+Severity: #error
+Expression: "$this > 1"
+
+// MedicationRequest
+Invariant: ch-dosage-3
+Description: "Patient instruction/free text dosage instruction, timing or as needed has to be specified"
+Severity: #error
+Expression: "patientInstruction.exists() or timing.exists() or asNeeded.exists()"
+
+// Dosage
+Invariant: ch-dosage-4
+Description: "For split dosage timing event and dose/rate are required"
+Severity: #error
+Expression: "sequence.exists() implies (timing.repeat.when.exists() and doseAndRate.dose.exists())"
+
+// MedicationStatement
+Invariant: ch-dosage-medstat
+Description: "If one dosage element is present, it should not have a sequence number. 
+              If more than one dosage element is present, the base entry has the sequence number 1."
+Severity: #error
+Expression: "(dosage.count() > 1 implies dosage.where($this.conformsTo('http://fhir.ch/ig/ch-emed/StructureDefinition/ch-emed-dosage') and sequence = 1).exists()) 
+         and (dosage.count() = 1 implies dosage.single().sequence.exists().not())"
+
+// MedicationDispense
+Invariant: ch-dosage-meddis
+Description: "If one dosage element is present, it should not have a sequence number. 
+              If more than one dosage element is present, the base entry has the sequence number 1."
+Severity: #error
+Expression: "(dosageInstruction.count() > 1 implies dosageInstruction.where($this.conformsTo('http://fhir.ch/ig/ch-emed/StructureDefinition/ch-emed-dosage') and sequence = 1).exists()) 
+         and (dosageInstruction.count() = 1 implies dosageInstruction.single().sequence.exists().not())"
+
+// MedicationRequest
+Invariant: ch-dosage-medreq
+Description: "If one dosage element is present, it should not have a sequence number. 
+              If more than one dosage element is present, the base entry has the sequence number 1."
+Severity: #error
+Expression: "(dosageInstruction.count() > 1 implies dosageInstruction.where($this.conformsTo('http://fhir.ch/ig/ch-emed/StructureDefinition/ch-emed-dosage-medicationrequest') and sequence = 1).exists()) 
+         and (dosageInstruction.count() = 1 implies dosageInstruction.single().sequence.exists().not())"
+
+

input/fsh/profiles/CHEMEDMedicationDispense.fsh

@@ -4,6 +4,7 @@ Id: ch-emed-medicationdispense
 Title: "CH EMED MedicationDispense (DIS)"
 Description: "Definition of the medication dispense for the medication dispense document"
 * . ^short = "CH EMED MedicationDispense (DIS)"
+* obeys ch-dosage-meddis
 * contained 1..
 * extension ^slicing.discriminator.type = #value
 * extension ^slicing.discriminator.path = "url"

input/fsh/profiles/CHEMEDMedicationRequest.fsh

@@ -4,6 +4,7 @@ Id: ch-emed-medicationrequest
 Title: "CH EMED MedicationRequest (PRE)"
 Description: "Definition of the medication request for the medication prescription document"
 * . ^short = "CH EMED MedicationRequest (PRE)"
+* obeys ch-dosage-medreq
 * contained 1..
 * extension ^slicing.discriminator.type = #value
 * extension ^slicing.discriminator.path = "url"

input/fsh/profiles/CHEMEDMedicationStatement.fsh

@@ -4,6 +4,7 @@ Id: ch-emed-medicationstatement
 Title: "CH EMED MedicationStatement"
 Description: "Definition of the medication statement for the medication treatment plan document (and as basis medication statement)"
 * . ^short = "CH EMED MedicationStatement (MTP and basis)"
+* obeys ch-dosage-medstat
 * contained 1..
 /* CH Core
 * extension ^slicing.discriminator.type = #value

input/pagecontent/changelog.md

@@ -12,6 +12,7 @@ All significant changes to this FHIR implementation guide will be documented on
    * Fix links from internal (CH EMED) to external (CH Term) artifacts
 * [#258](https://github.com/hl7ch/ch-emed/issues/258): CH Core base profiles as parent
 * [#252](https://github.com/hl7ch/ch-emed/issues/252): SCT code 246205007 'Quantity (attribute)' instead of UCUM human annotation {Piece} 'Stk.'
+* [#263](https://github.com/hl7ch/ch-emed/issues/263): Add additional constraints beside ch-dosage-1 to check, if the sequence number is present in split dosage elements
 
 ### STU 4 Sequence - v4.0.1 (2023-12-28)