Three years ago I took a blood lipids test as part of a physical
health checkup when I joined a new company.  My doctor told me that
the results were:
HDL 110
LDL 85
Triglycerides 75
My doctor also said that this was an unusually good profile. Recently
I took one of the instant cholesterol tests that a local pharmacy
offers for $15.  I didn't expect the test to be particularly accurate.
The test was done by taking a single drop of blood, and I had not
fasted for 12 hours beforehand- but I had fasted before I took the
blood lipid test in my checkup three years ago because the doctor told
me the test would not be accurate otherwise.  But an odd thing
happened when the people at the pharmacy put my drop of blood into
their cholesterol level testing machine.  They said they could not get
an accurate reading of my HDL level.  They said my HDL was "off the
scale" and they couldn't tell me exactly what it was because the scale
only goes up to 100.  This made me wonder about my HDL cholesterol
level, because I had assumed from what my doctor said that my HDL
level was good but within the normal range.  Could you tell me roughly
what percentage of people have an HDL level of 110 or so?  If it is
very unusual, is there anything that I should be worried about?  (By
the way, I am a woman in my 40?s.)

Your HDL level is very high indeed; 110 is about twice the average
level for women. In a 1998 study (linked below), your HDL level of 110
would place you in the 95th percentile of women in your age range. The
mean HDL level of women aged 35 to 44 in this study was about 62
mg/dl. In order to have comparable data, I have converted these
figures from mmol/L (millimoles/liter) to mg/dL (milligrams per
deciliter).

Scottish Health Survey 1998
http://www.show.scot.nhs.uk/scottishhealthsurvey/sh802-23.html

Regarding the conversion factor:

"All scientific journals are moving quickly toward using mmol/L
exclusively. Mg/dl won't disappear soon, and some journals now use
mmol/L as the primary unit but quote mg/dl in parentheses, reflecting
the large base of health care providers and researchers (not to
mention patients) who are already familiar with mg/dl...

To convert mmol/l of HDL or LDL cholesterol to mg/dl, multiply by 39.
To convert mg/dl of HDL or LDL cholesterol to mmol/l, divide by 39."

MSN Groups: mmol/L and mg/dl
http://groups.msn.com/DiabetesLiving/general.msnw?action=get_message&mview=0&ID_Message=9619&LastModified=4675480947006944223

Fortunately, HDL (high density lipoprotein) is one of the few things
that you can't get too much of. There are no health problems that are
caused by an elevated HDL level; quite the contrary. Higher is better.
People with high HDL levels are likely to live longer, have healthier
hearts, and maintain better cognitive function than those with lower
HDL levels.

I've gathered some online info for you. For reasons of copyright, I'm
posting just brief excerpts here. To read the entire article, just
click on the link under each excerpt.

"Cholesterol has to team up with protein to get through the blood
vessels. HDL, a high density lipoprotein made up of lipid (another
word for fat) and protein, has more protein than fat and appears to
carry the cholesterol it contains to the liver for excretion.
HDL-cholesterol is known as the "good" cholesterol. Therefore, you
want a high HDL number because that indicates a high level of this
good cholesterol in your blood. An average HDL number is in the
mid-forties range for a man and in the fifties range for a woman. A
HDL number less than 35 is considered a risk factor."

HealthGoods: Know Your Cholesterol Number
http://www.healthgoods.com/Education/Nutrition_Information/Cholesterol/know_your_cholesterol_number.htm

"The risk of atherosclerosis and heart attacks in both men and women
is strongly related to HDL cholesterol levels. Low levels of HDL
cholesterol are linked to a higher risk, whereas high HDL cholesterol
levels are associated with a lower risk.

Very low and very high HDL cholesterol levels can run in families.
Families with low HDL cholesterol levels have a higher incidence of
heart attacks than the general population, while families with high
HDL cholesterol levels tend to live longer with a lower frequency of
heart attacks.

Like LDL cholesterol, life style factors and other conditions
influence HDL cholesterol levels. HDL cholesterol levels are lower in
persons who smoke cigarettes, eat a lot of sweets, are overweight and
inactive, and in patients with type II diabetes mellitus.

HDL cholesterol is higher in people who are lean, exercise regularly,
and do not smoke cigarettes. Estrogen increases a person's HDL
cholesterol, which explains why women generally have higher HDL levels
than men do."

MedicineNet: Cholesterol
http://www.medicinenet.com/cholesterol/page3.htm

"It has been recognized for many years that high HDL is associated
with lower risk of heart disease, and the National Cholesterol
Education Program has recommended that an HDL level of less than *35
mg/dl should be regarded as a risk factor. In people lucky enough to
have a very high HDL (85 or more) the risk of heart disease remains
less than half the average level even when the LDL is quite high
(220)."

LifeClinic: What is HDL Cholesterol?
http://www.lifeclinic.com/focus/cholesterol/articleView.asp?MessageID=229

"In the United States, men's average HDL is about 45 and women's is
55. HDL under 40 is an especially bad sign, while anything over 60 is
considered good. Studies suggest that each single point of increase in
HDL is matched by a 2 percent to 3 percent reduction in heart
disease."

KATU: Health News
http://www.katu.com/health/story.asp?ID=66106

"Should patients with very high HDL-cholesterol be treated?

No treatment is necessary to lower serum HDL-cholesterol. 

A genetic deficiency of either serum cholesterol ester transfer
protein or hepatic lipase results in high HDL-cholesterol levels.

Other families with abnormally high serum HDL-cholesterol (where exact
mechanism has not been elucidated) and 'longevity syndrome' have been
described."

Healthy Heart: Should patients with very high HDL-cholesterol be treated?
http://www.healthyheart.org/Education/hdl/hdl11.htm

"What condition(s) can cause, or be associated with, elevated HDL
cholesterol levels?

Conditions that can cause elevated HDL cholesterol include, but are
not limited to:
- Hypothyroidism 
- Family history of high HDL cholesterol 
- Excessive exercise" 

eBioSafe: About Cholesterol
http://www.ebiosafe.com/Support_topic.asp?Which=17&Item=35

"Will you live to be 100? It may have more to do with your genes than
your lifestyle choices, according to a study on heart-healthy
cholesterol levels in centenarians.

Centenarians in the study had higher levels of 'good' HDL-cholesterol
compared to a control group of nearly 400 people in their 60s,
according to geriatrics researcher Nir Barzilai, M.D., an associate
professor of medicine at the Albert Einstein College of Medicine,
N.Y., and researcher in the study published in the Journal of the
American Geriatrics Society. What's more, Barzilai found the
centenarians had passed on their genetic defense to their children,
who also had higher HDL-cholesterol levels than others.

The findings suggest that some people are born with a unique genetic
protection against heart disease. Barzilai's study focused on 27
centenarians, 33 of their children and 26 of their children's spouses.

Many studies show high levels of high-density lipoproteins (HDL) in
your blood, lowers your risk of heart disease, while the 'bad' LDL
(low-density) cholesterol can increase your chances of developing
heart disease.

According to the study, women only needed to have high HDL-cholesterol
for longevity, while men needed both a high HDL-cholesterol reading
and a low LDL-cholesterol level. That may explain the statistical
findings on old age from the U.S. Census, which show that four out of
every five centenarians are women."

A to Z IQ Health: Genetic Clues to Healthy Aging
http://atoz.iqhealth.com/atoz/HealthUpdate/alert02062001.html

"At age 99, retired college professor Helen Reichert still has a deep
passion for music... A native New Yorker, Helen Reichert is part of a
first-of-its-kind study at Albert Einstein College of Medicine.
Research, reports CBS News Correspondent Byron Pitts, that could
unlock the key to living longer.

'There's something in the genes that protect them,' explained Dr. Nir
Barzilai... 'It seems that the centenarians and their children have an
unusually high level of what we call the good cholesterol.'

...Dr. Barzilai's research revealed that HDL, or good cholesterol, in
centenarians is twice that of others.

Helen's HDL is 103. The average middle-aged woman has an HDL level
that is around 55."

CBS News: The Secret to Longevity?
http://www.cbsnews.com/stories/2002/01/31/health/main326881.shtml

"Those with HDL of more than 75 may even be blessed with what's called
the 'longevity syndrome.'

'Just like your LDL can't be too low, your HDL can't be too high,'
says Dr. Lori Mosca, head of preventive cardiology at Columbia
University. 'I have patients with HDL over 120, and I tell them that's
probably how long they will live.'

Such off-the-chart amounts result from good genes, not healthy habits." 

IOPO News: Pills Aimed at Gunk in Arteries
http://www.iopo.org/news_detail.asp?ID=101

Google search strategy:

Google Web Search: "average hdl"
://www.google.com/search?hl=en&ie=UTF-8&q=average+hdl

Google Web Search: "elevated hdl"
://www.google.com/search?hl=en&ie=UTF-8&q=%22elevated+hdl

Google Web Search: "hdl" + "longevity"
://www.google.com/search?hl=en&ie=UTF-8&q=hdl+longevity

Do keep in mind that Google Answers is not a source of authoritative
medical advice; the material I've assembled for you is intended as
general information, and should not be viewed as any kind of
diagnosis, nor as a substitute for the services of a physician.

I hope this helps. If anything is unclear, or if a link doesn't work
for you, please request clarification; I'll be glad to offer further
assistance before you rate my answer.

Best regards,
pinkfreud