In today’s lesson we will be talking little bit about the last part of assessment
process -The Biochemistry. But before we look at some of the aspects of
biochemical assessment, there are few things that we need to keep in mind.
First and probably the most important thing we need to realize is, that rather
than looking at biochemical values, we have to look more closely at patients weight, and
food intake.Whether patient lost weight, is far more important than looking at his
albumin status. This will show us the real cause of any problems that may be associated
with his current condition , such as impaired wound healing, or immune system. The reason
for that is simple. There are many factors that affect lab values, and there are as many
human mistakes that can affect correct reading as well.For example improper handling of
blood samples, such as too long exposure to room temperature, may cause hemolysis-break
down of blood cells. This will have result in falsely increased number of cells.
Probably the most important thing when looking at lab values, is hydration status
of the patient. Whether patient is over hydrated or dehydrated will greatly affect
lab values.
Over hydration - will result in false low reading. This happens when patient has
edema. For that reason you may falsely assume that people with
diabetes, or with kidney disease having their albumin around 1.7-2.5,
may be at high risk for protein kcal malnutrition, while this low
values are simply caused by too much retained fluid, that causes
albumin to be dissolve in greater amount of fluid.
Dehydration - on the other hand, will have opposite effect. It will result in
falsely high values.For that reason you may incorrectly assume that
patient’s protein status is optimal by getting his albumin reading
at 3.5, while he is greatly dehydrated and the shortage of body fluid
causes albumin to be packed in smaller than normal amount of fluid, which
then results in falsely normal reading.
Many signs of dehydration and edema may be detected by simple eye examination.
- Edema -is most prominent at upper and lover extremities, especially ankles.
You may also notice that patient may have "big belly" which is called ascites.
It is caused by accumulation of fluid in the abdomen, mostly due to liver
failure in alcoholics or people with severe protein kcal malnutrition.
- Dehydration can be easily detected by papery thin skin, sunken eyes and
absence of changes in skin after indentation.
Another problem with using albumin as a detector of protein status, is that it has
fairly long half life. What it means is that it takes about 21 days for the albumin to
show any changes in the blood serum. That is why, when you are looking at the albumin
level, you are actually looking at the way this patient was eating 3 weeks ago.
Normal albumin levels are between 3.5 - 5
Pre albumin- Protein that transfers vitamin A and thyroxin. This test is more
expensive than regular albumin, and that is why it is not so commonly done.
It is however much more accurate, because it's half life is only 7
days. For that reason it is mostly used in some hospitals before surgical
procedures. It shows patient's protein status within past 7 days.
Immune status
Lots of pt in the hospital have low immune status because they are prot kcal
malnourished.You simply need the protein to make the white blood cells, and the kcal
to spare the protein.
To calculate your total lymphocyte count TLC= all your WBC x lymphocyte count
The problem here ,however is that lymphocyte count is usually not available unless doctor
orders CBC- complete blood count + differential. The differential is what includes
the lymphocytes.
Normal lab values for lymphocytes are 2500 and above. If you have
lymphocytes around 400 you have seriously compromised immune system.
click here for sample calculation quiz