The most common way to get false negative chlamydia and gonorrhea tests would be from testing too soon after you had sex or by urinating too soon if testing with the urine test.
With gonorrhea, most results are accurate after 7 days. With chlamydia, most results are accurate after 2 weeks but it can take up to 6 weeks. Testing at 2 weeks after contact is a good time for a test because it should pick up gonorrhea and would most likely detect chlamydia.
With the urine test, it is best if you do not urinate for 2 hours before doing the test. If you urinate before this time period it can affect the accuracy of the test. You only have to wait 1 hours with some the new urine tests.
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