If a large percentage of the PSA is accounted for by free PSA, it means
your slightly elevated PSA is likely from a cause other than cancer.  
Some urologists don't want to mess with free PSA - they want to go
straight to a biopsy.  A colleague's friend had a PSA somewhat in your
range, but on a rising trajectory.   The urologist didn't want to do a
free PSA.   He went straight to a biopsy -- and the results came back
negative.    It would be interesting to know what a free PSA test would
have said.

This man had his PSA checked every 6 months for a while afterwards, but
his wife now tells me he's back to yearly checkups.   It could be
something like that will be in store for you, too.   That would be
good!  

I remember seeing tables on the web that gave the odds, back when I had
a PSA of 4.79.   My primary physician ordered a free PSA for me at the
same time he made me an appointment with a urologist.   I went home and
learned about free PSA on the web.   When I went for my urologist
appointment, I read my free PSA results upside down on the paper I saw
through the receptionists window, and knew I was in trouble.   It was
somewhere on the order of 10 percent.   By the time I got my blood
pressure checked a few minutes later, it was one of the highest ones I
ever recorded.   Even the word "biopsy" hadn't elevated my blood
pressure back at the time I first got my PSA results, even though it got
my attention even more than the words, "it could be cancer" did.  

(The other way to get a few minutes advance warning on your results is
to watch how the female assistants who handle your records talk to
you.   If they look at you and talk to you as though you're a guy,
you're OK.   If they avert their eyes and treat you like dead meat,
you're not.)  

JohnG

AJ...One might use terms such as sensitivity and specificity to answer
your question.  It turns out that, in the sub 4.0 total PSA range, the
free PSA test is pretty sensitive (it identifies most of the true
positives and doesn't give too many false negatives), but also not
very specific (there are a lot of false positives mixed in with the
true negatives).  So as the authors note in the following abstract,
the free PSA test does provide another measure of risk assessment,
even when used in the sub 4.0 total PSA range, but does not do much to
eliminate unnecessary biopsies.  Your PSA values are right at the
bottom edge of the range studied, so I would expect these findings to
apply to you...Best wishes and good health, Ron

The Journal of Urology 2002; 168(3):922-925
Robustness of Free Prostate Specific Antigen Measurements to Reduce
Unnecessary Biopsies in the 2.6 to 4.0 ng./ml. Range
KIMBERLY A. ROEHL; JO ANN V. ANTENOR; WILLIAM J. CATALONA*
ABSTRACT
Purpose:
Prostate specific antigen (PSA) cutoffs lower than 4.0 ng./ml. are
being evaluated more frequently but lower PSA cutoffs increase the
number of prostatic biopsies. PSA exists in several forms free and
complexed to proteins. Percent free PSA is lower in men with prostate
cancer. Accordingly, free PSA and complexed PSA have been used to
distinguish between cancer and benign disease in the diagnostic gray
zone of 4 to 10 ng./ml. to eliminate unnecessary biopsies. There are
limited data on the robustness of free PSA measurements in the 2.6 to
4.0 ng./ml. total PSA range.
Materials and Methods:
We evaluated percent free PSA measurements to discriminate between
cancer and benign conditions in 965 consecutive volunteers in a
prostate cancer screening study who underwent prostatic biopsy for a
PSA of 2.6 to 4.0 ng./ml. and had benign digital rectal examination.
Results:
Overall 25% of men had cancer detected. A 25% free PSA cutoff detected
85% of cancers and avoided 19% of negative (cancer-free) biopsies,
while a 30% free PSA cutoff detected 93% of cancers and avoided only
9% of negative biopsies. Of those men who underwent radical
prostatectomy 132 (80%) had pathologically organ confined tumors. Only
5% of these tumors fulfilled the published pathological criteria for
possibly clinically unimportant tumors.
Conclusions:
Percent free PSA provides risk assessment but does not eliminate many
unnecessary prostatic biopsies while maintaining a high sensitivity in
the narrow total PSA range of 2.6 to 4.0 ng./ml.

If you have not had surgical removal of the prostate, that 2.7 is not very
serious.  Your physicians are being ultra-cautious.  Continue annual blood
draws for PSA measurement and if it increases by 50% or more in a year, but is
still less than 4 or so, get a free PSA.  If then that is less  than 25%, get a
biopsy.  If the PSA is greater than 4 but the free PSA is less than 25%, take a
course of antibiotics and check again- then if numbers don't improve, get a
biopsy.  I am not a physician, so this is un-professional personal opinion.

AJ,

The next step is Free PSA.  And I don't know why it would be unreliable.

However, just to ease your fears, I think it unlikely that you would have a
2.7 four months ago, 2.4 now, and at 47 be diagnosed with Prostate Cancer.
I'm not saying it's impossible, but the statistically, unlikely.  It is more
likely you have BHP and possible, lacking any other symptom, that you have
no prostate problem at all.

You're welcome to join our club, of course, but frankly, we just don't want
you.