Laboratory Specimen Handoff

Summary

Passing of specimens between Laboratory Automation Systems (LAS) and Specimen Processing Devices (SPD) is an integral part of clinical laboratory operation. But current LAS and SPD vendors have little guidance on how to implement specimen handoff. HL7 and CLSI AUTO3-A provide some direction, but do not provide specific guidance for individual handoff workflows.

In the absence of any industry guidance, specimen handoffs are defined on an ad hoc basis. This approach tends to ensure that each vendor will take a unique path, even though specimen handoff interfaces share a high degree of commonality among most vendors.

There clearly exists a need for fully specified interface protocols to reduce the time and costs associated with managing specimen handoff in clinical laboratories. The IHE-LAB Committee is the appropriate entity to create and promote such solutions. Prior work by the Committee on the LDA profile is evidence of that need.

The Laboratory Specimen Handoff (LSH) profile will provide standardized workflows for the most common laboratory specimen handoff use cases.

Benefits

The LSH Profile will advance the IVD industry by providing a common, fully specified framework for the most common specimen handoff use cases, based on the collective experience of active participants from across the IVD industry.

Promoting a consistent understanding of specimen handoff will have a number of benefits.

1. Reduced design burden for Specimen Processing Devices
2. Reduced design burden for the laboratory automation systems to which SPDs are attached
3. Comprehends handoff pitfalls that may not be apparent to an individual development team
4. Provide a generally accepted foundation upon which the industry can build

Details

The Laboratory Specimen Handoff (LSH) Integration Profile facilitates laboratory specimen passing by providing detailed message transactions used during specimen handoff.

The LSH Integration Profile will cover the two most common handoff use cases in the clinical laboratory. Implementation will occur in phases, in order of commonality.

Use Case 1 - Single-Specimen Point-in-Space Acquisition

The Specimen Transport Manager (STM) notifies SPD that a specimen container is en route to the SPD. The SPD prepares for specimen arrival, typically receiving work order steps (by some means other than LSH). Upon arrival, the STM presents the specimen for acquisition. Acquisition is typically aspiration. The SPD acquires the specimen from the container, without taking possession of the container. Automation removes the specimen from the aspiration position.

Use Case 2 - Single-Specimen Container Transfer

SPD takes posession of specimen container. Workflow TBD

Additional Use Cases

Additional phases may address other specimen handoff use cases. Likely additions are "Multi-Specimen Container Transfer" and "Assay Availability".

Systems Affected

Actors & Transactions

Order Filler

Receives the laboratory work for each patient. Produces Work Orders.

Automation Manager

Container for all lab automation features, inclusive of Analyzer Manager, Process Manager and Specimen Transport Manager

The internals of this actor are intentionally vague, as they are out of scope for IHE-LAB activities.

Analzyer

Instrument that automates IVD testing.

Pre/Post Processor

Device that automates specimen preparation.

Three actors will be affected by the LSH Integration Profile - Specimen Transport Managers (STM), Analyzers and Pre/Post Processors (PPP). Examples of STM Actors are laboratory automation tracks and specimen transport robots. Analyzer Actors are typically in-vitro diagnostic devices. Examples of PPP Actors are centrifuges and aliquotters.

Standards and Systems

Profile Status: Preliminary content below (Pre-Supplement)

Documents: Underlying Standards:

• HL7
• CLSI AUTO5-A (HL7 Chapter 13)

Use Cases

Use Case 1 - Single-Specimen Point-in-Space Acquisition

Steps

1. Device status changes, and is available to process STM specimens
   1. Device available for STM specimens is a prerequisite for use case

   
   

2. STM optionally sends "Status Request" to Device
   1. LAB-41 transaction
   2. STM may send a "Status Request" message unsolicited at any time, to trigger a "Status Update" message

   
   

3. Device sends Status Update to STM
   1. LAB-42 transaction
   2. Trigger is either the Device status change or the receipt of a Status Request (LAB-41)

   
   

4. Specimen arrives at STM
   1. The meaning of "arrives" is system-dependent
      1. May mean first awareness by STM system, physical arrival at an STM subsystem, or any other point during STM handling

   
   

5. STM Creates a Specimen Transport Plan
   1. Determines that SPD is a destination in the plan

   
   

6. STM sends "Prepare for Specimen Acquisition" to Device
   1. LAB-43/Command transaction
   2. Includes container identifier (SID)
   3. Optionally includes container information
   4. Should be sent as soon as practical to allow Device to have maximum preparation time. Actual requirement will vary by implementation
   5. Multiple "Prepare for Specimen Acquisition" messages may be received before a specimen container arrives
   6. Extensions -
      1. Message malformed at application level
         1. Send "Prepare Complete" message rejecting specimen due to malformed message
         2. STM does not present specimen
         3. Use case ends
      2. Device not in a state to receive specimens from automation
         1. Send "Prepare Complete" message rejecting specimen due to invalid Device state
         2. STM does not present specimen
         3. Use case ends

   
   

7. Device prepares to receive the specimen
   1. Preparation behavior is out of scope for this use case. Typically, Device queries for, and receives, Work Order Steps and schedules the specimen per the internal scheduling algorithm
   2. Extensions -
      1. No WOS for specimen
         1. Send "Prepare Complete" message rejecting specimen due to unknown specimen (no WOS)
         2. STM does not present specimen
         3. Use case ends
      2. At least one WOS can be performed, but not all WOS
         1. (analyze this further. not strictly necessary, but may have value when, say, reagent for one assay is depleted)
         2. Send "Prepare Complete" message accepting specimen, but indicating only partial capability
         3. Continue with use case
      3. "Prepare Complete" is not received
         1. (Consider options - Specimen is in an unknown state)

   
   

8. Device sends "Prepare Complete" to STM
   1. LAB-43/Response transaction
   2. Extensions -
      1. Message malformed at application level
         1. Send "Prepare Complete" message rejecting specimen due to malformed message
         2. STM does not present specimen
         3. Use case ends
      2. Device not in a state to receive specimens from automation
         1. Send "Prepare Complete" message rejecting specimen due to invalid Device state
         2. STM does not present specimen
         3. Use case ends

   
   

9. STM positions specimen for acquisition by Device
   1. Extensions-
      1. Error prevents specimen from being positioned (e.g. mechanical error)
         1. Use case continues at Step 9, with STM sending "Start Specimen Acquisition" with "Cancel"
            1. Clears specimen from LD
            2. LD also (still) sends "Specimen Acquisition Complete" message when specimen is cleared
         2. STM does not present specimen
      2. "Start Specimen Acquisition" is not received by Device
         1. Device will no longer consider specimen valid, and will reject specimen if it arrives
         2. Use case ends

   
   

10. STM sends "Start Specimen Acquisition" to Device
    1. LAB-43/Command transaction
    2. STM may not move container between sending this message and receiving the "Specimen Acquisition Complete" message (Step 10)
    3. Includes container identifier (SID)
    4. STM starts an Acquisition timeout timer
    5. Extensions-
       1. Message malformed at application level
          1. Send "Specimen Acquisition Complete" message rejecting specimen due to malformed message
          2. Use case ends
       2. Device not in a state to receive specimens from automation
          1. Send "Specimen Acquisition Complete" message rejecting specimen due to invalid Device state
          2. Use case ends
       3. Device is not aware of the specimen
          1. No "Prepare for Specimen Acquisition" was received, or "Prepare for Specimen Acquisition" was received but "Start Specimen Acquisition" did not arrive within time constraint
          2. Send "Specimen Acquisition Complete" message rejecting specimen due to unknown specimen
          3. Use case ends
       4. Missed scheduling window
          1. Specimen presented too late for aspiration
          2. Optional, Device implementation may or may not have an arrival time dependency
          3. Send "Specimen Acquisition Complete" message rejecting specimen due to missed scheduling window
          4. Use case ends

    
    

11. Device acquires specimen
    1. Device only manipulates specimen
    2. Container is not moved
    3. Extensions-
       1. Device detects a non-recoverable error that potentially obstructs specimen movement
          1. Device stops acquiring specimen
          2. Device stops movement within the mechanical envelope of the container
          3. Device sends "Specimen Acquisition Complete" message indicating an obstruction error
          4. STM initiates no movement within the mechanical envelope of the container
          5. Use case ends
             1. User intervention is required to resolve the issue
             2. STM may not move container
       2. Device detects a specimen error
          1. Does not include obstructions
             1. Device mechanics can still move safely
          2. Device stops acquiring specimen
          3. Device sends "Specimen Acquisition Complete" message indicating a specimen error
             1. Includes error type, if known
                1. Insufficient Specimen
                2. Bubble in Specimen
                3. Clotted Specimen
                4. Other
             2. Use case ends
                1. STM may remove specimen
       3. "Specimen Acquisition Complete" is not received by STM
          1. (Consider options - Specimen is in an unknown state - Power could have been removed with pipettor in the specimen)

    
    

12. Device sends "Specimen Acquisition Complete" to STM
    1. LAB-43/Response transaction
    2. STM may assume that all Device apparatus is removed from the container envelope, and will remain removed until the next "Start Specimen Acquisition" message
       1. Only exception is an "Obstruction Error"
    3. Extensions-
       1. Message malformed at application level
          1. (Consider options - Specimen is in an unknown state - Power could have been removed with pipettor in the specimen)

    
    

13. STM continues with specimen transport plan
    1. Container is now under the control of the STM

    
    

Use Case 2 - Single-Specimen Container Transfer

This workflow is TBD.

Transactions

LAB-41 Status Request

The Status Request transaction defines the message used by the Specimen Transport Handler (STH) to request Device status with respect to specimens arriving on the track interface.

Interaction Diagram

Interaction Model

Trigger	Specimen Transport Handler (STH) has a need to obtain the Device status with respect to track specimens
Direction	STH > Device
Roles	STH	Keep track of Device's status to know when it can process specimens from the track
	Device	Provides status for track interface
Responsibility	STH	Provide request for status
	Device	Acknowledge request, and initiate a Status Update transaction (LAB-42)

HL7 2.5.1 Implementation

HL7 2.5.1, Chapter 13, specifies the ESR^U02 Message for status requests. Its usage in LAB-41 is shown below.

ESR^U02 Message

Segment ID	Meaning	Usage	Cardinality
MSH	Message Header	M	[1..1]
EQU	Equipment Detail	M	[1..1]

ACK^U02 Message

Segment ID	Meaning	Usage	Cardinality
MSH	Message Header	M	[1..1]
MSA	Message Acknowledge	M	[1..1]
[{ERR}]	Error	C(M/X)	[0..*]

LAB-42 Status Update

The Status Update transaction defines the message used to report Device status to the Specimen Transport Handler (STH), with respect to specimens arriving on the track interface.

Interaction Diagram

Interaction Model

Trigger	Device status changes, or the Device receives a Status Request (LAB-41).
Direction	Device > STH
Roles	Device	Keep the STH updated with current status
	STH	Keep track of Device's status to know when it can process specimens from the track
Responsibility	Device	Provide Device LAS status
	STH	Acknowledge message, and update STH behavior based on Device status

HL7 2.5.1 Implementation

HL7 2.5.1, Chapter 13, specifies the ESU^U01 Message for status updates. Its usage in LAB-42 is shown below.

ESU^U01 Message

Segment ID	Meaning	Usage	Cardinality
MSH	Message Header	M	[1..1]
EQU	Equipment Detail	M	[1..1]

ACK^U01 Message

Segment ID	Meaning	Usage	Cardinality
MSH	Message Header	M	[1..1]
MSA	Message Acknowledge	M	[1..1]
[{ERR}]	Error	C(M/X)	[0..*]

LAB-43 Command/Response

LAB-43 Command

The Command transaction defines the Specimen Transport Handler (STH) message used to command the Device to prepare for specimen processing.

Interaction Diagram

Interaction Model

Trigger	STH needs to command the Device to perform an LAS operation
Direction	STH > Device
Roles	STH	Initiate device commands
	Device	Respond to STH commands
Responsibility	STH	Provide Device command
	Device	Acknowledge message, and provide an LAB-43 Response when command is complete

HL7 2.5.1 Implementation

HL7 2.5.1, Chapter 13, specifies the EAC^U07 Message for equipment commands. Its usage in LAB-43 is shown below.

EAC^U07 Message

Segment ID	Meaning	Usage	Cardinality
MSH	Message Header	M	[1..1]
EQU	Equipment Detail	M	[1..1]
{	-- COMMAND Begin	M	[1..1]
ECD	Equipment Command Detail	M	[1..1]
SAC	Specimen Container Detail	RE	[0..1]
}	-- COMMAND End	M	[1..1]

1. SAC
   1. Required if STM knows SID. Otherwise, optional.
   2. Include container dimensions, if known
2. EQU.3 (Equipment State)
   1. Review codes provided in table. Determine of we need to augment with new codes.
      1. Coordinate with Dmytro on this. He has experience in this area.
3. ECD.2 (Remote Control Command)
   1. PS - Prepare for Specimen
   2. SA - Start Specimen Acquisition
   3. Allow command option to only send ACK^U07 on error
   4. Enhanced acknowledge mode

   
   

ACK^U07 Message

Segment ID	Meaning	Usage	Cardinality
MSH	Message Header	M	[1..1]
MSA	Message Acknowledge	M	[1..1]
[{ERR}]	Error	C(M/X)	[0..*]

LAB-43 Response

The Command transaction defines the Analyzer response used to communicate the outcome of a command from the Specimen Transport Handler (STH).

Interaction Diagram

Interaction Model

Trigger	Device needs to communicate the outcome of a command.
Direction	Device > STH
Roles	Device	Provide a response to STH commands when commands are complete
	STH	Confirm the device response
Responsibility	Device	Provide command response
	STH	Acknowledge message, and update STH behavior based on Device response

HL7 2.5.1 Implementation

HL7 2.5.1, Chapter 13, specifies the EAR^U08 Message for equipment commands. Its usage in LAB-43 is shown below.

EAR^U08 Message

Segment ID	Meaning	Usage	Cardinality
MSH	Message Header	M	[1..1]
EQU	Equipment Detail	M	[1..1]
{	-- COMMAND Begin	M	[1..1]
ECD	Equipment Command Detail	M	[1..1]
SAC	Specimen Container Detail	M	[1..1]
ECR	Equipment Command Response	M	[1..1]
}	-- COMMAND End	M	[1..1]

ACK^U08 Message

Segment ID	Meaning	Usage	Cardinality
MSH	Message Header	M	[1..1]
MSA	Message Acknowledge	M	[1..1]
[{ERR}]	Error	C(M/X)	[0..*]