ACLA Comments on the Result Reference Range for USCDI v5

The American Clinical Laboratory Association (ACLA) comments pertain to the burden of using the Unified Code for Units of Measure (UCUM). ACLA believes the vocabulary standard, UCUM, should be recommended, but not required. Laboratories should be allowed to use units of measure other than UCUM. The unit of measure provided by the instrument manufacturers, including FDA authorized, cleared, or approved method, is the standard that laboratories need to adhere to for result reporting. We recommend conversations and adoption from instrument manufacturers is incumbent for the adoption of UCUM to be viable. We would also recommend the ONC solicit feedback from CAP and CLIA on their stance on the need for conversion to UCUM. The UCUM can be a preferred standard, but it should not be required for all tests. Currently, there is a large base of units of measure that are in use across trading partners. To convert these units to UCUM would be problematic, difficult to achieve and time consuming. While ACLA acknowledges UCUM as an option for standardized vocabulary for units of measure it is crucial to recognize and understand the limitations of the UCUM coding system and the impact of key issues identified by ACLA prior to universal adoption.

• UCUM has codes for ALL US customary units (e.g., UCUM guide §35 U.S. survey lengths, and §37 U.S. volumes). However, these will not necessarily have the same string representation that a given laboratory uses (see UCUM GUIDE http://unitsofmeasure.org/ucum.html). It also includes codes for all non-arbitrary unit of measure (UoM), includes many arbitrary UoM such as Somogyi units, and has a way to include strings (which will not be computable for any arbitrary units -- but arbitrary units are never computable in the sense that they can be interconverted).
• There are issues with transmission of unusual or unrecognizable characters (e.g. ‘*’ or ‘^’, and descriptions sometimes use ‘#’ and ‘&’) which cause errors in some sending and receiving systems. These are restricted characters that cause issues in data exchanges including HL7.
• Some recommended UCUM units exceed the HL7 prescribed field lengths for the coded element of 20 characters (e.g. nmol{BCE}/mmol{creat}, %{normal_pooled_plasma}). For example, some state public health systems are unable to accept more than 20 characters in the unit of measure HL7 field.
• The mandate to report all units of measure in a UCUM format could impact patient safety. 
  • There may be a potential for discrepancies between the units of measure directed by instrument and/or reagent vendors in their package insert/operator’s manual for result reporting of a particular test vs. the UCUM units identified for that test. 
  • The instruments that process the specimens may or may not use UCUM standard units. There is a risk in converting results into a unit of measure that is different than the original unit of measure. 
    • Conversions cannot always be achieved to equivalency.
    • Even if it is accurately converted, it does not ensure that providers will always interpret it correctly.
    • It is common for conversion algorithms to encounter errors. While the problem with that is self-explanatory, a second issue may not be.  The value and the units of message occupy two separate HL7 fields.  Should a numeric value encounter an error, and the translation process choses to handle the issue by leaving the value as it was received but incorrectly modifies the units of measure (assuming the value algorithm performed correctly), there could be a disconnect between the value and units of measure that could greatly impact the interpretation of the results, and by extension, the health of the patient.
  • At present, units can be very confusing and unpredictable and almost impossible to use for computer purposes like decision support and quality assessment. We have seen more than 30 different representations of units for the number RBCs e.g.  10^12/Lit  bill/liter,  10*12/liter., etc.

Comment

Highly support and agree with this new data element. The Result Reference Range will ensure consistency across the healthcare ecosystem. For example, if a Blood Glucose Level was sent without the appropriate range, then the receiving organization may mis-categorize the result as normal or abnormal.

APHL supports inclusion of this data element

APHL supports the inclusion of this data element as well as the assignment of UCUM as the expected vocabulary - depending on the units of measure expressed in the package insert, which need to be used for reporting and a translation may not always be possible, so it may not always be possible to use UCUM.

ACLA Comment on Laboratory: Result Reference Range

The American Clinical Laboratory Association (ACLA) comment pertains to the Applicable Standard(s): The Unified Code for Units of Measure (UCUM) and the estimate of overall burden: Very low burden.  ACLA Comments: Using only the UCUM as a standard is problematic and the burden would be very high using this standard. The UCUM cannot be used when it is not supported by the analytic procedure’s documentation for an FDA authorized, cleared, or approved method. Existing interfaces should not be required to update to the UCUM. (Note: the FDA approved units must be used for reporting, regardless of the standard used).     

ACLA Comment on Laboratory: Result Reference Range

The American Clinical Laboratory Association (ACLA) comment pertains to the Applicable Standard(s): The Unified Code for Units of Measure (UCUM) and the estimate of overall burden: Very low burden.  ACLA Comments: Using only the UCUM as a standard is problematic and the burden would be very high using this standard. The UCUM cannot be used when it is not supported by the analytic procedure’s documentation for an FDA authorized, cleared, or approved method. Existing interfaces should not be required to update to the UCUM. (Note: the FDA approved units must be used for reporting, regardless of the standard used).     

CAP Comment on Result Reference Range

• Data Class: Laboratory
• Data Element: Result Reference Range
• CAP Comment: The CAP applauds the ONC’s decision to add this data element to USCDI v4, as this data element represents the upper and lower limit of test values expected for a designated population of individuals and is required by CLIA. However, the CAP would like to note that a simple text field for this data element (as in HL7 2.5.1) is inadequate for interoperability. The CAP recommends that this Result Reference Range data element be aligned with the FHIR observation.referenceRange element, which supports discrete low and high values, normalValue (expected value), and text based reference descriptions. For this data element, the CAP recommends UCUM for units and SNOMED CT for non-numerical values.

THIA Comment on Laboratory: Result Reference Range

The Texas Health Informatics Alliance (THIA) Policy and Standards Working Group supports the proposal for result reference range; however, we are cognizant of the fact that the reference range may change depending on an individual’s ethnic or gender make-up. Many reference ranges are based on young, healthy males. Consequently, reference ranges can be problematic due to (lack of) representation of different demographics like sex, age, gender, ethnicity. Notably, there are issues with how reference ranges are developed between institutions; however, it would take a lot of work to re-establish all reference ranges. It might be helpful to have a warning note based on heritage and/or some language to raise the issue of reference ranges not being focused on the pertinent population. Further exploration of the best way to present these nuances is needed and the proposal should consider requirements on establishing complete representation of the population being served.

CDC's Consolidated Comment for USCDI v4

• Physicians, nurses, epidemiologists, and anyone who is using laboratory reports for patient care and public health, including patients, will depend on the reference range for the correct interpretation of the provided laboratory results. It must be available to the authorized person who ordered the test and, if applicable, the individual responsible for using the test results. It is required by CLIA for all laboratory reports, 493.1291(d) Standard: Test report. Link: https://www.ecfr.gov/current/title-42/chapter-IV/subchapter-G/part-493/subpart-K/subject-group-ECFR9482366886d579f/section-493.1291
• Comments from NACCHO: NACCHO supports including the data element reference range. Most local health departments (LHD) do not have laboratory expertise, so having the reference range on a test is critical. While joining the reference range based on a LOINC code is possible, most LHDs do not have the license to LOINC, nor the expertise needed to associate the reference range. In addition, laboratory custom tests offered by commercial labs do not have a standardized reference range and must be provided.
• Comments from CSTE: CSTE agrees with CDC's recommendation for this data element.