And doctors don't respond in this forum.
Why do you think that there was pre-cum in the specimen you provided? Generally start of the stream is recommended for Chlamydia urine test (and No clean catch), so no, it should not matter if pre-cum was included in the sample. Why would doctors ask a patient to ejaculate for a test, when it can be done by using urine? Don't understand the logic of your question at all.