A single abnormal finding does not support a diagnosis. You may have a chlamydia infection which does not cause symptoms of dysuria in many women. The WBCs in the urine indicating normal is determined by the laboratory and though 0-4 WBC in most labs is considered normal, one additional WBC is meaningless. The MCHC at 36.2 again is not really elevated when in most labs the normal range is 33-37. Keep your appointment with your doctor and request an evaluation for chlamydia. I hope this is helpful.
Yes it is possible that the sample was contaminated. LE is not a specific marker but only suggestive. LE is an enzume released by WBCs.and is considered to indicate any type of inflammation, not any specific disease. The fact that you are not sexually active mitigates against STD. Each time you take blood tests you may expect to find minor variations in the results. This is common! If you had Chlamydia, which I doubt based on the additional information you provided, treatment with antibiotics would need to be specific for the infection. Not all antibiotics are effective on all infections. At this point I would not be concerned about having AIDS which only occurs when someone is HIV positive. To ease your concerns totally have a GYN examination that includes a GYN Probe which can determine any significant STD. All in all I think you are dealing with a lab error so don't be overly concerned.