Submitted by jkegerize on
ACLA Comment on the Result Unit of Measure 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.
Submitted by jkegerize on
ACLA Comment on Result Unit of Measure for Draft USCDI Version 5
The American Clinical Laboratory Association (ACLA) appreciates the opportunity to comment on the data element, Result Unit of Measure.
The ACLA comments pertain to the burden of using the Unified Code for Units of Measure (UCUM). Using only the UCUM as a standard is problematic and the burden for laboratories would be very high. 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).
APPLICABLE VOCABULARY STANDARD(S)
Standards listed are required. If more than one is listed, at least one is required unless otherwise noted. Where an applicable vocabulary standard has not been identified, this field will remain empty.
ACLA comments:
ACLA suggests “preferred” replace “required” under the heading “Applicable Vocabulary Standard(s), or please clarify what is meant by “required” when a standard value (e.g., UCUM) does not exist. Unified Code for Units of Measure (UCUM) are not always available and UCUM is not implementable in every circumstance.