How should LNMT range items returned from LNMT be designed on lab forms?

There are different options to design a lab form for LNMT.

Option 1 – Common form with 4 textboxes

This option requires 4 textboxes for every lab test on the eCRF. The textboxes should display:

• Lower limit
• Upper limit
• Unit
• Within Range Flag

LNMT populates the Within Range flag with a value indicating if the lab result is In-range (Y), Out of Range (N), or Invalid (INV).

With this option, you get separate columns in SAS for all 4 test boxes. However, if the lab normal was entered as < 100 instead of 0 to 100, LLN is populated with -2147483648 and ULN is populated with 100.

Option 2 – Common form with 2 textboxes

This option requires 2 textboxes for every lab test on the lab eCRF. The textboxes should display the following values:

• Range and Unit textbox: Lower limit, Upper limit, and Unit. This textbox displays lab normal ranges along with their unit.
• Within Range textbox: Within Range. This textbox indicates if the lab results are In-range, Out of Range or Invalid.

With this option, not all lab tests will have lab normal ranges expressed as a numeric range with defined lower and upper limits. Some lab tests can character-based normal values (for example, “Negative”, “Neg”, “No” or “N”), some lab test can have normal ranges defined using operators and others (for example, “Normal cholesterol is < 200 mg/dL”), and some lab tests can have no units associated with test results (for example, “pH” or “specific gravity”).

However, using this options means you have to differentiate in SAS LLN, ULN, and Unit.