The SCD segment was introduced in HL7 v2.6 to support equipment status update (ESU) messaging from sterilizers, washer-disinfectors, and other anti-microbial reprocessing devices. It carries the detailed per-cycle parameters — start/stop timing, temperatures, phase durations, alarms — for a single sterilization or decontamination run. SCD continues unchanged in structure through v2.7, v2.7.1, v2.8, v2.8.1, and v2.8.2; this page reflects the v2.8.1 HAPI definition.
Purpose
SCD reports a single anti-microbial cycle's measured and configured parameters. It is produced by a reprocessing device after a cycle starts, runs, or completes, and lets a CMMS, instrument tracking system, or sterile-processing application record cycle telemetry against a sterilizer (identified by an accompanying SDD/SCP) and, where relevant, against the patient identifiers whose instruments were processed.
Typical uses:
- Reporting cycle start time, total cycle time, and completion for a load.
- Recording max/min temperatures, sterilize time, exhaust time, and dry time.
- Flagging abort, alarm, door-open, over/under-temperature, and reading-failure conditions.
- Capturing operator unload identity and the procedure code or patient list associated with the load.
Used in
SCD travels inside Equipment Status Update (ESU) and related anti-microbial reprocessing messages produced by sterilizers, washer-disinfectors, and endoscope reprocessors. A single ESU typically carries one SDD (sterilization device data), one or more SCP (sterilization configuration parameter) segments, and one SCD per reported cycle. Downstream consumers include sterile processing department (SPD) tracking systems, asset management, and quality reporting platforms.
Field-by-field reference
The table below lists every field in SCD as defined by the HAPI v2.8.1 model. Seq is the dotted-identifier used in HL7 (SCD-1, SCD-2, ...). Req marks fields the standard requires; all others are optional and may be omitted. Repeat is Y where the field is defined as repeating in the v2.8.1 javadoc. Table # lists the HL7 user/HL7-defined table where one is well established.
| Seq | Name | Data Type | Length | Req | Repeat | Table # | Description |
|---|---|---|---|---|---|---|---|
| SCD-1 | Cycle Start Time | tm | — | R | — | — | Time the anti-microbial cycle began |
| SCD-2 | Cycle Count | nm | — | O | — | — | Sequential count of cycles on device |
| SCD-3 | Temp Max | cq | — | O | — | — | Maximum temperature reached during cycle |
| SCD-4 | Temp Min | cq | — | O | — | — | Minimum temperature reached during cycle |
| SCD-5 | Load Number | nm | — | O | — | — | Identifier of load processed in cycle |
| SCD-6 | Condition Time | cq | — | O | — | — | Duration of the conditioning phase |
| SCD-7 | Sterilize Time | cq | — | O | — | — | Duration of the sterilization exposure phase |
| SCD-8 | Exhaust Time | cq | — | O | — | — | Duration of the exhaust phase |
| SCD-9 | Total Cycle Time | cq | — | O | — | — | Total elapsed time for the cycle |
| SCD-10 | Device Status | cwe | — | O | — | — | Coded status of the reprocessing device |
| SCD-11 | Cycle Start Date/Time | dtm | — | O | — | — | Date and time the cycle began |
| SCD-12 | Dry Time | cq | — | O | — | — | Duration of the drying phase |
| SCD-13 | Leak Rate | cq | — | O | — | — | Measured chamber leak rate |
| SCD-14 | Control Temperature | cq | — | O | — | — | Target control temperature for cycle |
| SCD-15 | Sterilizer Temperature | cq | — | O | — | — | Measured sterilizer chamber temperature |
| SCD-16 | Cycle Complete Time | tm | — | O | — | — | Time the cycle finished or aborted |
| SCD-17 | Under Temperature | cq | — | O | — | — | Under-temperature deviation observed |
| SCD-18 | Over Temperature | cq | — | O | — | — | Over-temperature deviation observed |
| SCD-19 | Abort Cycle | cne | — | O | — | — | Indicates the cycle was aborted |
| SCD-20 | Alarm | cne | — | O | — | — | Alarm condition raised during cycle |
| SCD-21 | Long in Charge Phase | cne | — | O | — | — | Charge phase ran longer than expected |
| SCD-22 | Long in Exhaust Phase | cne | — | O | — | — | Exhaust phase ran longer than expected |
| SCD-23 | Long in Fast Exhaust Phase | cne | — | O | — | — | Fast-exhaust phase ran longer than expected |
| SCD-24 | Reset | cne | — | O | — | — | Device was reset during the cycle |
| SCD-25 | Operator - Unload | xcn | — | O | — | — | Operator who unloaded the cycle |
| SCD-26 | Door Open | cne | — | O | — | — | Chamber door opened during cycle |
| SCD-27 | Reading Failure | cne | — | O | — | — | Sensor reading failed during cycle |
| SCD-28 | Cycle Type | cwe | — | O | — | — | Coded type of sterilization cycle run |
| SCD-29 | Thermal Rinse Time | cq | — | O | — | — | Duration of the thermal rinse phase |
| SCD-30 | Wash Time | cq | — | O | — | — | Duration of the wash phase |
| SCD-31 | Injection Rate | cq | — | O | — | — | Rate at which chemistry was injected |
| SCD-32 | Procedure Code | cne | — | O | — | — | Procedure associated with the load |
| SCD-33 | Patient Identifier List | cx | — | O | Y | — | Patients whose instruments were processed |
| SCD-34 | Attending Doctor | xcn | — | O | — | — | Attending doctor for the procedure |
| SCD-35 | Dilution Factor | sn | — | O | — | — | Chemistry dilution factor applied |
| SCD-36 | Fill Time | cq | — | O | — | — | Duration of the chamber fill phase |
| SCD-37 | Inlet Temperature | cq | — | O | — | — | Temperature of inlet water or fluid |
Most-used fields
- SCD-1 Cycle Start Time and SCD-11 Cycle Start Date/Time — paired in modern implementations; SCD-11 carries the full date+time and SCD-1 the legacy time-only value.
- SCD-7 Sterilize Time, SCD-9 Total Cycle Time, SCD-12 Dry Time — the core duration parameters audited by sterile processing departments.
- SCD-15 Sterilizer Temperature and SCD-3/SCD-4 Temp Max/Min — primary thermal evidence that the cycle achieved its parameters.
- SCD-19 Abort Cycle, SCD-20 Alarm, SCD-26 Door Open, SCD-27 Reading Failure — exception flags that decide whether a load is releasable.
- SCD-25 Operator - Unload and SCD-33 Patient Identifier List — close the audit loop between cycle, operator, and patients.
Version differences (2.6 to 2.8.2)
- v2.6 — SCD introduced with fields 1–37 to support anti-microbial cycle reporting alongside SDD and SCP.
- v2.7 — Coded fields migrated from CE to CWE/CNE (Device Status, Cycle Type, Procedure Code, alarm-style flags). SCD-11 Cycle Start Date/Time moved to the DTM data type, which now carries an explicit precision indicator.
- v2.7.1, v2.8, v2.8.1 — No new fields; data-type tightening only. SCD-33 Patient Identifier List remains repeating; all other fields remain non-repeating.
- v2.8.2 — No field additions or structural changes to SCD.
Common mistakes
- Sending only SCD-1 (TM) and omitting SCD-11 (DTM). Modern consumers expect SCD-11 because it carries the date as well as time.
- Treating SCD-19/20/24/26/27 as free-text. They are CNE — coded with no exceptions — and must use a value from the device vendor's published table.
- Putting durations as plain numbers in CQ fields. CQ requires both quantity and units (
90^sor15^min). - Repeating fields other than SCD-33. Only Patient Identifier List repeats in v2.8.1.
- Using SCD without the partnering SDD/SCP that identify the device and its configuration — downstream systems cannot correlate the cycle without them.
Examples
Minimal SCD
SCD|103045|||||||||||||||103915
Fully-populated SCD
SCD|103045|4471|134.5^Cel^UCUM|132.1^Cel^UCUM|7782|600^s^UCUM|240^s^UCUM|180^s^UCUM|1320^s^UCUM|RUNNING^Cycle running^HL70667|20260610103045|420^s^UCUM|0.8^mbar/min^UCUM|134.0^Cel^UCUM|134.3^Cel^UCUM|110530|0.0^Cel^UCUM|0.4^Cel^UCUM|N^No^HL70532|N^No^HL70532|N^No^HL70532|N^No^HL70532|N^No^HL70532|981^WELLS^MARIA^L^^^^^SPD^^^^^EI|N^No^HL70532|N^No^HL70532|PREVAC134^Pre-vacuum 134C^HL70702|0^s^UCUM|0^s^UCUM|0^mL/min^UCUM|ORTH-TKA^Total Knee Arthroplasty Tray^HL70088|44991782^^^STER^MR~44991783^^^STER^MR|78231^MERRIDEW^ELIAS^J^^DR^^^STAFF^^^^^DN|1^10^:^1|180^s^UCUM|14.0^Cel^UCUM
Annotated breakdown
SCD|103045 Cycle Start Time (TM): 10:30:45 local
|4471 Cycle Count: 4,471st cycle on this device
|134.5^Cel^UCUM Temp Max: 134.5 C
|132.1^Cel^UCUM Temp Min: 132.1 C
|7782 Load Number: 7782
|600^s^UCUM Condition Time: 600 s
|240^s^UCUM Sterilize Time: 240 s exposure
|180^s^UCUM Exhaust Time: 180 s
|1320^s^UCUM Total Cycle Time: 22 min
|RUNNING^... Device Status: RUNNING (coded)
|20260610103045 Cycle Start Date/Time (DTM): 2026-06-10 10:30:45
|420^s^UCUM Dry Time: 7 min
|0.8^mbar/min^UCUM Leak Rate
|134.0^Cel^UCUM Control Temperature
|134.3^Cel^UCUM Sterilizer Temperature
|110530 Cycle Complete Time (TM): 11:05:30
|0.0^Cel^UCUM Under Temperature
|0.4^Cel^UCUM Over Temperature
|N^No^HL70532 Abort Cycle: No
|N^No^HL70532 Alarm: No
... Remaining CNE flags: all No
|981^WELLS^MARIA... Operator - Unload (XCN)
|PREVAC134^... Cycle Type: Pre-vacuum 134 C
|ORTH-TKA^... Procedure Code: TKA tray
|44991782^^^STER^MR~44991783^^^STER^MR Patient Identifier List (repeats)
|78231^MERRIDEW^... Attending Doctor (XCN)
In-context excerpt: ESU sterilization cycle report
MSH|^~&|STERILOG|SPD-WEST|TRACKING|HOSP|20260610110600||ESU^U07^ESU_U07|MSG00098231|P|2.8.1
EQU|STR-A12^Steris Amsco V-PRO|20260610110600|RUNNING^Operational^HL70667
SDD|STR-A12|STER-V-PRO|VAPORIZED-H2O2|Steris|V-PRO maX 2
SCP|STR-A12|VAPORIZED-H2O2|STANDARD-LUMEN|55^min^UCUM|2.5^mbar^UCUM|50^Cel^UCUM
SCD|103045|4471|56.4^Cel^UCUM|49.8^Cel^UCUM|7782||||3300^s^UCUM|RUNNING^Cycle running^HL70667|20260610103045|360^s^UCUM||50.0^Cel^UCUM|50.3^Cel^UCUM|110530|||N^No^HL70532|N^No^HL70532||||||981^WELLS^MARIA^L^^^^^SPD^^^^^EI|N^No^HL70532|N^No^HL70532|VPRO-NL^V-PRO Non-Lumen^HL70702
In-context excerpt: aborted cycle with alarm
MSH|^~&|STERILOG|SPD-EAST|TRACKING|HOSP|20260610141522||ESU^U07^ESU_U07|MSG00098299|P|2.8.1
EQU|STR-B07^Getinge HS66|20260610141522|ALARM^Alarm raised^HL70667
SDD|STR-B07|HS66|STEAM|Getinge|HS66 LS
SCP|STR-B07|STEAM|134C-PREVAC|3^min^UCUM|3.04^bar^UCUM|134^Cel^UCUM
SCD|135210|9912|131.2^Cel^UCUM|122.0^Cel^UCUM|7791|600^s^UCUM|0^s^UCUM|120^s^UCUM|780^s^UCUM|ALARM^Alarm^HL70667|20260610135210|0^s^UCUM||134.0^Cel^UCUM|131.2^Cel^UCUM|141522|2.8^Cel^UCUM|0^Cel^UCUM|Y^Yes^HL70532|Y^Yes^HL70532|N^No^HL70532|N^No^HL70532|N^No^HL70532|N^No^HL70532|664^OKAFOR^DANIEL^^^^^^SPD^^^^^EI|N^No^HL70532|N^No^HL70532|PREVAC134^Pre-vacuum 134C^HL70702
FHIR mapping
There is no segment-level ConceptMap published in the HL7 v2-to-FHIR Implementation Guide for SCD. In practice, integrators map SCD content to a combination of resources:
- The device identified by the partnering SDD becomes a Device (or DeviceMetric for individual sensors).
- Each cycle's measured parameters (SCD-3/4/7/9/12/15) map naturally to Observation resources keyed to the Device and timestamped at SCD-11.
- Exception flags (SCD-19/20/26/27) often become DetectedIssue or Observation with a
severity/statusaxis. - SCD-33 Patient Identifier List, when present, becomes the
Observation.subjectset for the load.
Because the IG does not normatively cover SCD, treat any local mapping as project-specific and document the choices in your interface specification.
Engine considerations
- HAPI parses SCD with all 37 fields at v2.8.1. SCD-33 is exposed as a repeating CX accessor; the other fields are scalar. Validate CQ unit codes against UCUM in your application layer — HAPI does not enforce code-system membership.
- Mirth Connect / NextGen Connect handles SCD generically. Most projects use a JavaScript template per device vendor because cycle-type vocabularies (SCD-28) and alarm codes (SCD-20) differ vendor-to-vendor.
- Cloverleaf / Rhapsody typically forward SCD untouched to the tracking system; transforms are usually limited to remapping device IDs to a master device catalog.
- Iguana / Lyniate Iguana users frequently flatten SCD into per-cycle JSON for downstream analytics rather than re-emitting HL7.
- Trigger event handling: ESU/U07 in v2.8.1 uses the
ESU_U07structure with one EQU, one SDD, one or more SCP, and one or more SCD per cycle. Engines should route on the EQU device ID, not the MSH sending application alone, because a single integration endpoint typically multiplexes many sterilizers.
How Vorro parses and produces SCD
The Vorro integration platform models SCD as a strongly-typed cycle record bound to the device asserted by the accompanying SDD. When parsing inbound ESU messages, Vorro:
- Normalizes SCD-1 and SCD-11 into a single
cycleStartedAttimestamp, preferring SCD-11 where present and falling back to SCD-1 plus the message date. - Coerces every CQ field (SCD-3/4/6/7/8/9/12/13/14/15/17/18/29/30/31/36/37) into a
{value, unit}pair and validates the unit against the device's published UCUM list, raising a soft warning rather than rejecting the message when a unit is unknown. - Promotes the CNE flag fields (SCD-19/20/21/22/23/24/26/27) into a single
exceptionsset on the cycle, preserving the original coded value and table for replay. - Expands SCD-33 into a list of patient references resolved against the master patient index, attaching load → patient links to the SPD ledger.
When producing SCD from device telemetry, Vorro guarantees SCD-1 and SCD-11 are co-populated, emits CQ values in UCUM, and refuses to emit a cycle record without an accompanying SDD/SCP pair so downstream systems always have device context.
Related pages
- SDD — Sterilization Device Data
- SCP — Sterilization Configuration Parameter
- ESU — Automated Equipment Status Update
