translating units

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  • #49005
    Jay Lyle
    Participant

    VistA reports 6690-2 Leukocytes with a variety of unit strings. Most can be confidently assumed to be be synonymous with the LOINC example unit of 10*3/uL (K/cmm, K/UL, K/MM3, X10-3/UL, K/cu mm, 10.e3/uL, X1000/uL). Some, however, have the same dimension and magnitude, but use different magnitudes in the expression, e.g., BILL/L, 10E9/L.

    In these cases, we recommend using a valid UCUM string, but preserving the source magnitudes, e.g., 10*9/L. Is this in line with others’ practice?

    #270871
    Pam Banning
    Participant

    Hi Jay,

    From the information we share at Laboratory LOINC committee, there are organizations that store original units of measure and have a separate translated UCUM stored. We’re meeting this Thursday, June 6th, and I’ll sidebar with Stan Huff from his Intermountain Health days.

    Sincerely,

    Pam Banning

    co-chair Lab LOINC Committee

    #270888
    Pam Banning
    Participant

    Hi Jay,

    I emailed Stan instead of waiting for the in person meeting. Here is his response:

    <span style=”color: #1f497d;”>I have no objection to what Jay proposes, but things would work fine just using the units sent (BILL/L, 10E9/L) because, if I have done the math right, the decimal point does not change. Or to put it another way these last two examples are still exact synonyms for 10*3/uL.  </span><span style=”color: #1f497d;”>BILL/L and 10E9/L are not valid UCUM representations.  The UCUM representation for billion is 10*9 , so I think the official UCUM units for billions per liter would be 10*9/L.  Stan</span>
    <p class=”MsoNormal”><span style=”color: #1f497d;”> PB thinks you’re both in agreement.</span></p>
     
    <p class=”MsoNormal”><span style=”color: #1f497d;”>     </span></p>
    <p class=”MsoNormal”><span style=”color: #1f497d;”> </span></p>

    #435986
    Jay Lyle
    Participant

    Many thanks.

    I have another case.

    For 2823-3 POTASSIUM, the example unit is mmol/L, and the recorded unit is MEQ/L (the equivalent UCUM being meq/L). I’m no laboratorian, and I have no idea when mmol is or is not synonymous with meq, but my assumption is that since they may differ, we use meq/L. However, it’s not entirely clear that this is a valid use of  2823-3. I can see using unit magnitudes different from the example, but not different unit dimensions. Is this a problem?

    #435987
    Pam Banning
    Participant

    Hi Jay,

    In the instance of only one element (K for potassium- from the periodic table, Na for sodium, etc) knowing the molecular weight is the equivalent weight. So for K or Na or Cl (chloride) mmol/L = mEq/L.  <span style=”display: inline !important; float: none; background-color: #ffffff; color: #333333; font-family: Georgia,’Times New Roman’,’Bitstream Charter’,Times,serif; font-size: 16px; font-style: normal; font-variant: normal; font-weight: 400; letter-spacing: normal; orphans: 2; text-align: left; text-decoration: none; text-indent: 0px; text-transform: none; -webkit-text-stroke-width: 0px; white-space: normal; word-spacing: 0px;”>A brief tutorial can be found at Wikipedia on equivalent weight. </span> This is NOT a complete formula for compounds (combinations of Sodium Chloride for example), so please don’t create a basic transformation algorithm without regard to chemical composition.

    All the best,

    Pam

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