DEAR ABBY: I am writing in response to the letter from the woman who received a positive diagnosis of chlamydia. After 16 years of a completely faithful marriage, I, too, was diagnosed as having this sexually transmitted disease. Worse yet, I received a telephone call from the nursing assistant informing me that my name would be sent to the county health department, and I should have all my partners treated!

I was so shocked I could hardly speak! I asked if there was any other way I could have gotten such a disease and was told that it was transmitted only through sexual intercourse, and either I - or my partner - must have had sexual contact with someone who had the disease.Two days later, I insisted that I be retested. The test came back negative!

My advice to the woman wondering about her spouse - wonder instead about your test results, the lab processing and the doctor's method of handling your case!

I recognize that medical staff must regularly deal with patient denial, but I knew I had not been unfaithful, and I was certain my husband had not been either. The nursing assistant, however, insisted that one of us must have strayed. We have been taught to respect medicine and the people in it as all-knowing. They are human, they make mistakes, but unfortunately, the news they deliver can destroy people. We are wise to question and remain calm if we possibly can.

If my husband and I did not have such a trusting relationship, the false test could have done great damage. - ALSO FROM ARIZONA

DEAR ALSO: My mail has brought an alarming number of letters from readers with tales of testing identical to yours. Chlamydia should always be tested by taking a culture.

DEAR ABBY: For almost 10 years, "Leon" has been my best friend. Leon has seen me through the death of a parent, an attempted suicide, a bout with cancer and the chemotherapy that followed.

Here is where I need your advice, Abby. I am getting married in a few months. I've selected my bridesmaids and flower girl, but I would like to have Leon stand up with me as my "MAN of honor." I've discussed this with my fiance, and even though he thinks it sounds a bit odd, it's perfectly all right with him.

My mother, on the other hand, feels that I would be the laughingstock of our town. I say, if people want to laugh at a solid friendship, let them. Incidentally, Leon and I never were lovers, only very close friends.

What is your advice? Do you think it would be inviting rumors to have a man stand up with me? (My mother thinks so.)

My fiance has offered to let Leon be an usher, but I want him to be there in the role of the person who has been the nearest and dearest friend of my adult life.

Please tell me your feelings. Would you frown upon such a choice? - KANSAS SUNFLOWER

DEAR SUNFLOWER: Would I frown on selecting a man to honor as your best friend? Certainly not! Friendship knows no gender. Some bridegrooms have a chosen "best woman" instead of "best man."

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