sqlite function datetime() in tcl

I have a tcl script that inserts some values into a sqlite database table.  I have updated the table to have 2 new fields, both of which are datetime fields.

table layout:

Patient ID

Lab Order

Requester Order

Order Date/Time

Result Date/Time

My old TCL statement to place the patient and order numbers into the table was this:

set result [catch {DBCMD eval {INSERT INTO hms2allscriptsxlate VALUES ($PIDhmspat,$ORChmsorder,$ORCasorder) }}]

I would like to use the SQLite function datetime() to populate the new fields.  I tried the following statement, but it did not work:

set result [catch {DBCMD eval {INSERT INTO hms2allscriptsxlate VALUES ($PIDhmspat,$ORChmsorder,$ORCasorder, datetime(), null) }}]

Do I need quotes around the SQLite function?  Or is there an equivalent TCL function?