The book that I have studied said “我看了化验结果。” but I’m wondering if “我看化验结果了” make sense or not. If the second one can be used, what’s the difference?
了 in 我看了化验结果 is an aspect marker that indicates the verb 看 (read) is a completed action. You can add the final practice 了 to 我看了化验结果 and write 我看了化验结果了 (the final practice 了 indicates the sentence is finished, adds emphasis to the sentence and/or soften the tone of speech)
了 in 我看化验结果了 is in the position of final practice, but it can be treated as an aspect marker if you consider '看化验结果' as a verb phrase, meaning the act of 'reading the test result' is a completed act. But it is not the way people normally talk even you can argue that it is technically grammatical. It is more likely that people would treat the 了 at the end as a final practice and interpret 我看化验结果了 as 'I'll read the test result now')
in 我看了化验结果了, the 了 after 看 is an aspect marker and the 了 at the end is a final particle