contains evaluates as True if the value matches all or part of the specified text. The matching does not take into account whether the text is upper or lower case.
Similarly, does not contain evaluates as True if the value does NOT match the specified text.
contains is only used for text values, not numeric values.
For example, given the following case fragment,
Cholesterol 7.3 5.6 6.1 Triglyceride 1.1 0.8 pending ClinicalNotes PREG PREGNANT
Triglyceride contains “pending”
ClinicalNotes contains “preg”
ClinicalNotes does not contain “OnT4”
Also
at least 2 ClinicalNotes contain “preg”
For very finely controlled text matching on all samples in a case, consider using a Text Attribute.