Monday, March 29, 2004
Hypoglycemia - Blood Suger Levels
Hypoglycemia - Blood Suger Levels
The medical laboratory definition of normal is the range of values that
includes the middle 95% of the normal population. That didn't come out as
clearly as I would have liked so let me show you with an example. The lab will
take 100 normal people (none of them known to have a disease that effects the
test being done). They will take the values of all the normal people, throw out
the top 2.5% and the bottom 2.5% and call the remaining 95% their "normal
range" for that test. In reality one does not have to take 100 or even 1000
people to define the normal range. One can use statistics to define it. By
calculating the average (mean) and something called the standard deviation and
assume the test is distributed in a Guassian Distribution, the normal range is
2 standard devations below the average to 2 standard deviations above the
average. Trust me that a normal range can be calculated from a sample of people
without disease, and will include 95% of of those disease free people.
The normal range is a usefull concept but has some limitations. One limitation
is that there are 5% of people without any disease (2.5% below the normal and
2.5% above the normal) who will be labeled abnormal. Another limitation is that
some people with a disease that is being tested for may still fall into the
normal range. This is because the definition of normal only used people without
the disease. Put another way, some people with the disease may test as normal
because there is some overlap of the people with the disease, with the test
results of normal people.
Okay, with that preface in mind, let's look at the normal plasma glucose level,
derived from a population of normal individuals.
This data comes from 52 premenopausal women and 12 men. If you want to look up
the article it was written by TJ Mariwee and JE Tyson and is called, "Stabilization
of Plasma Glucose During Fasting." and comes from the New England Journal of Medicine,
volume 291, pages 1275-1278, in 1974.
The normal values differ between men and women and will be presented
separately. The normals are:
WOMEN
fasting 68-110 mg/dl
24 hrs fasting 34-81 mg/dl
48 hrs fasting 37-62 mg/dl
72 hrs fasting 15-68 mg/dl
MEN
fasting 66-111 mg/dl
24 hrs fasting 55-103 mg/dl
48 hrs fasting 50-99 mg/dl
72 hrs fasting 50-85 mg/dl.
Let me reitterate, these come from normal individuals (no known diabetes and no
hypoglycemic symptoms). I will make a comment on these figures. Some normal
women can get very low glucose levels and have no hypoglycemic symptoms.
Therefore a low glucose level does not give someone the diagnosis of
hypoglycemia.
posted by Anonymous
PermaLink @ 2:36 PM
The medical laboratory definition of normal is the range of values that
includes the middle 95% of the normal population. That didn't come out as
clearly as I would have liked so let me show you with an example. The lab will
take 100 normal people (none of them known to have a disease that effects the
test being done). They will take the values of all the normal people, throw out
the top 2.5% and the bottom 2.5% and call the remaining 95% their "normal
range" for that test. In reality one does not have to take 100 or even 1000
people to define the normal range. One can use statistics to define it. By
calculating the average (mean) and something called the standard deviation and
assume the test is distributed in a Guassian Distribution, the normal range is
2 standard devations below the average to 2 standard deviations above the
average. Trust me that a normal range can be calculated from a sample of people
without disease, and will include 95% of of those disease free people.
The normal range is a usefull concept but has some limitations. One limitation
is that there are 5% of people without any disease (2.5% below the normal and
2.5% above the normal) who will be labeled abnormal. Another limitation is that
some people with a disease that is being tested for may still fall into the
normal range. This is because the definition of normal only used people without
the disease. Put another way, some people with the disease may test as normal
because there is some overlap of the people with the disease, with the test
results of normal people.
Okay, with that preface in mind, let's look at the normal plasma glucose level,
derived from a population of normal individuals.
This data comes from 52 premenopausal women and 12 men. If you want to look up
the article it was written by TJ Mariwee and JE Tyson and is called, "Stabilization
of Plasma Glucose During Fasting." and comes from the New England Journal of Medicine,
volume 291, pages 1275-1278, in 1974.
The normal values differ between men and women and will be presented
separately. The normals are:
WOMEN
fasting 68-110 mg/dl
24 hrs fasting 34-81 mg/dl
48 hrs fasting 37-62 mg/dl
72 hrs fasting 15-68 mg/dl
MEN
fasting 66-111 mg/dl
24 hrs fasting 55-103 mg/dl
48 hrs fasting 50-99 mg/dl
72 hrs fasting 50-85 mg/dl.
Let me reitterate, these come from normal individuals (no known diabetes and no
hypoglycemic symptoms). I will make a comment on these figures. Some normal
women can get very low glucose levels and have no hypoglycemic symptoms.
Therefore a low glucose level does not give someone the diagnosis of
hypoglycemia.
posted by Anonymous
PermaLink @ 2:36 PM
