interpreting your lab tests

8/10/2019 Interpreting Your Lab Tests

http://slidepdf.com/reader/full/interpreting-your-lab-tests 1/3

INTERPRETING YOUR LAB TESTS

A key to taking control of your health is learning to monitor your immune system. The bulk of immune monitoring is done through avariety of blood tests. Learning how to read and understand your laboratory tests can be quite frustrating. This article will provide

basic information to help with this process. Because different labs reports results a little differently, it may be wise to ask your doctorto help you read the results as well.

There are some basic rules which hold true for nearly all laboratory tests:

. !ifferent laboratories can get different results from the same sample of blood. "ake sure you ask your doctor which lab asused if it was noted on the report.

#. Laboratories can make mistakes. $f your results have changes dramatically since your last test, have it run again.

%. "ost lab values have to be interpreted along with other clinical and laboratory data in order to develop a meaningfuldiagnosis. &ery seldom will only one value give all of the answers.

'. Laboratory values differ according to age, se(, current medications, etc. Therefore, the interpretation of these values needsto be done with these parameters in mind.

). The *normal* range is the value that is normal for a person who does not have +$& infection. or e(ample, a low cholesterolvalue in an +$& positive individual is not uncommon.

COMPLETE BLOOD COUNT (CBC)

The complete blood count - B / is one of the most common tests offered by a doctor. $t is a routine test used toevaluate the blood and general health. Asymptomatic, +$& positive people should have this test done twice a year.0ymptomatic people should have their B done at least every three months. Additionally, if you are on anti1+$&medication you might have to have this test more often. A B measures all of the following parameters: red bloodcell count -2B /, white blood cell count -3B /, hemoglobin, hematocrit, three red cell indices, and the white celldifferential. 4latelet cunts are sometimes included in a B .

RED BLOOD CELL COUNT (RBC)

The 2B count is the number of red blood cells in a cubic millimeter of blood. The 2B s are the cells produced inthe bone marrow that carry o(ygen to your tissues. The normal rage is '.) 1 )15 million6mm %for men and '.7 1 ).%million6mm % for women. A slightly decreased value is not cause for alarm as many individuals with +$& havevalues below the normal range. +owever, a markedly decreased value should be thoroughly investigated. A personwith significant low 2B count can have symptoms of fatigue, shortness of breath, and appear pale in colour. Alow 2B count can be due to progressive +$& illness or to certain medications or both. A8T, for e(ample, cansuppress the production of 2B s in some people. A decrease in the 2B count usually causes a decrease in thehemoglobin and hematocrit values.

WHITE BLOOD CELL COUNT (WBC)

The 3B count is the number of white blood cells in a cubic centimeter of blood. The primary function of thesecells is to prevent and fight infections. There are many different types of white blood cells that play specific roles infighting infections. These specific types of 3B s can be measured in a white cell differential. 9ormal 3B countis from ',)77 to ,777. The 3B count can be decreased for a variety of reasons: certain medications decreasetheir production in the bone marrow, minor viral infections which you may not even be aware of, stress, andopportunistic infections can all change 3B counts. &alues markedly decrease should be cause for concern, sinceduring this situation one is more susceptible to other infections.



HEMOGLOBIN

(ygen is carried to the tissues via hemoglobin in the red blood cells. A normal hemoglobin level is ' 1 ; g6dl for men and # 1 < g6dl for women. A slow progressive decline in hemoglobin is often seen in people with A$!0. Thisis usually due to a decline in the number of 2B s produced in the bone marrow. Any drug which causes asuppression of the bone marrow will decrease the hemoglobin levels. $n most cases it*s a matter of balancing the

effects of the drug with it*s potential side effects. 3hen the side effects become too great, either the drug must bediscontinued or the dose reduced to a tolerable level. A drug which mimics the action of the hormoneerythropoietin -a.k.a. 4rocrit, =4 and newer brand names/, has it*s effect on the bone marrow causing the

production of new 2B s. $t has provided great relief to thousands of individuals of people with +$& and kidneydialysis patients. =4 has enabled many people to stay on bone marrow suppressive drugs without the need for transfusions.

HEMATOCRIT

The hematocrit is the percent of the cellular components in your blood to the fluid or blood plasma. This test is oneof the truest markers of anemia. 9ormal values for men are '71)'> ad for women, %?1'?>. A decrease inhematocrit is always seen with a decrease in hemoglobin. These two values are linked to one another.

MEAN CELL VOLUME (MCV)

The mean cell volume or " & is the most important of the 2B indices. $t is a measure of the average si@e of the2B . or those individuals taking A8T the " & will always be normally elevated, i.e. greater than 77. &itaminB # and olic Acid deficiency also causes increases in " &. 9ormal " & levels are ;7 1 5<.

PLATELETS

4latelets are cellular fragments which are necessary for the blood to clot. 3hen activated by trauma, plateletsmigrate to the site of in ury where they become *sticky* 1 adhering to the in ured site and helping to form a fibrinclot or scab. 9ormal platelet values are )7,777 1 ')7,777. $n some individuals, +$& itself causes a decrease in thenumber of platelets. therwise, drugs can also cause low platelet counts. =ven though counts are considered low

below )7,777, most people can survive without the threat of internal bleeding with counts above )7,777. n veryrare occasions, the number of platelets present are adequate, but for unknown reasons they don*t function correctly.Any malady involving one*s platelets can be a potentially serious condition.

WHITE CELL DIFFERENTIAL

The white cell differential counts 77 white cells and differentiates them by type. This gives a percent of thedifferent kinds of white cells in relation to one another. The three main types are: polymorphonuclear cells -4"9s/,lymphocytes, and monocytes. 4"9s are increased during bacteria infections, while lymphocytes are decreasedwith viral infections. $ncreased monocytes are sometimes seen in chronic infections. 9ormal percent of 4"9s is ))1 ;7>. #) 1 ')> is the normal number of lymphocytes, and # 1 7> is normal for monocytes.

There are a wide range of blood chemistry tests which are done on individuals either routinely or for specific reasons. 0ome of the

ones pertaining to +$& are mentioned below.

CHOLESTEROL

holesterol levels, as mentioned earlier, are routinely decreased in +$& positive individuals. $t*s not understoodwhy this occurs, but it is thought to be related to altered metabolism. 9ormal cholesterol levels are )7 1 #)7mg6dl.

AMYLASE



Amylase is an en@yme that is secreted in the mouth by the salivary glands and also in the pancreas. $t can be anearly warning sign of acute pancreatitis when elevated. ddI can cause problems with the pancreas in a smallnumber of people taking the drug. 9ormal amylase levels are #) 1 #) milliunits6ml.

CPK or CK

4 or is an en@yme that*s found in the brain and muscles of the body. 0trenuous e(ercise as well as heartattack can cause increases in 4 . This makes clear the point of elevating an abnormal test result in the conte(t of other factors. "yopathy, dysfunction6distress with the muscles, can sometimes be confirmed with an elevated 4 ."yopathy is usually caused by +$& but can also b due to A8T, especially at higher dosages. 9ormal levels of thisen@yme are 1 ;7 milliunits6ml -%7 degrees7 or )) 1 ?7 milliunits6ml -%? degrees/. &alues will be slightly lower for women.

LIVER FUNCTION TESTS

Liver function tests include ) 1 < individual tests which collectively can help determine the status of ones liver.=levated liver en@ymes are most often caused by certain medications. The +$& positive population also has a high

prevalence of hepatitis. At least ' different viruses are known to cause hepatitis, all leading to increased liver function tests. Therefore, compound factors can be at work. $f liver en@ymes are only moderately elevated, mostdoctors will take a *wait and see* attitude, monitoring them over a period of a few weeks to a few months. +owever,if elevation is quite high, the underlying factor must be found. This might very well be one of the medications thatyou are currently taking. The names of these liver function tests include 0C T, 0C4T, alkaline phos, total

bilirubin, and L!+.

KIDNEY FUNCTION TESTS

Two tests which measure kidney function are the BD9 and reatinine. The usefulness of these two tests in an +$& positive individual usually relates to medications possibly to(ic o the kidneys. +ence kidney function is monitoredin this way. oscarnet is an e(ample of a drug which can cause renal to(icity. 9ormal BD9 levels are 7 1 #7mg6dl. 9ormal levels of reatinine are 7.< 1 . mg6dl.

LYMPHOCYTE SUBSETS

The category of lymphocyte subsets includes absolute counts and percentages of !' and !; cells as well asother parameters. Dsually the number and percent of B cells is included and the number and percent of alllymphocytes -e(cept those called *natural killer* or 9 cells/. Lymphocytes are broken down mainly into !'-E/cell and !;-E/ cells. $t is well known that +$& causes a slow progressive decline in the number and percent of

!'-E/ cells in most individuals. There are e(ceptions. 0ome people progress in their disease rapidly and othersdon*t seem to progress much at all after more than # or % years. normal !' counts are %)7 1 )77. The role of

!; cells is less clearly understood. =arly on in the epidemic, high !; cell counts caused inversion of the!': !; ratio and was thought to adversely affect illness. 9ow it is generally believed that elevated !; counts

are advantageous since it*s thought to keep +$& somewhat constrained. 9ormal !; cell counts in an +$&negative person is #?) 1 ?;7.

interpreting your lab tests

Documents