Mystery Illness.....!!

My lovely wife's been poorly of late
So I took her to see the nurse
To find out what the problem was
As it seemed to be getting worse!
They tested her and took some blood
Said they'd have the results, next day
I didn't sleep a wink that night
For fear of what they would say!
Morning came, and the nurse did call
The conversation filled me with dread
There was another patient; same name as my wife
They'd "mixed up the results", she said
How do we sort out this problem?
I'm not looking for anyone to blame
But surely you can tell the difference
Their symptoms can't be the same
"You're quite correct in your logic
So it should be straight forward," Mr Lee
One has advanced Alzheimers
The other is a positive HIV!!
I had to know which illness she had
I decided to find out that day
So I helped my wife into a taxi
And he dropped her 5 miles away
I know its a tad on the cruel side
But on this journey I had to send her
Its clear to me, that if she finds her way home
Then sex is off the agenda.....!!