If you do not have diabetes, you usually have only small amounts of ketones in your blood and urine. If you have diabetes, however, you may have high amounts of ketones and acid, a condition known as ketoacidosis. This condition can cause nausea, vomiting, or abdominal pain and can be life threatening.
You may use urine dipsticks to rapidly and easily measure the ketones in your urine. You dip a dipstick in your urine and follow the instruction on the package to see if you have a high amount of ketones.
c) Blood Cholesterol Tests
Blood tests serve a number of purposes when diagnosing people with conditions or who are at risk of developing heart disease. These include diagnosing and identifying such as abnormal or levels. They can be used to determine if a has occurred and measure the extent of damage to the heart. They are also used to monitor the patient’s progress during treatment.
Cholesterol is carried in the blood combined with specific proteins in complexes known as lipoproteins. These are classified as chylomicrons, high density, low density, very low density and intermediate density lipoproteins (HDL, LDL, VLDL, and IDL respectively). They vary in terms of both protein and relative lipid composition. Total cholesterol values reflect the total amount of cholesterol in the lipoproteins. Raised serum cholesterol (hypercholesterolemia) is one of the major risk factors associated with an increased risk of coronary heart disease.
Cholesterol and triglyceride tests are usually performed as part of a or lipid panel. This test measures and fat-like substances in the blood which, if abnormally high, are known to be related to heart disease. The different fats measured include:
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Total . High total cholesterol level is associated with heart disease.
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cholesterol. Low-density lipoprotein or “bad” cholesterol that is associated with .
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cholesterol. High-density lipoprotein or “good” cholesterol” protects against heart disease.
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. High levels are associated with heart disease.
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(very low density lipoprotein). This is another carrier of fat in the blood and is associated with atherosclerosis.
How to test for Blood Glucose
It is now possible for the individual with diabetes and the health-care professional to measure and record blood glucose levels frequently with portable devices. In the hospital, blood glucose monitors (BGM) are often used instead of routine laboratory glucose testing methods to quickly obtain blood glucose concentrations from patients. On most BGMs, a drop of whole blood is placed on a blood glucose test strip (compatible with the BGM) before or after the strip is inserted into the monitor to determine the blood glucose concentration. BGMs are in vitro diagnostic tests for quantitative and semi-quantitative measurement of glucose by glucose oxidase, dehydrogenase, or hexokinase based methodologies. They are different to the larger clinical chemistry analyzers or the dedicated glucose analyzers used in hospitals to perform glucose testing on plasma, serum and urine.
a) Glucose Oxidase BGMs
Most BGM devices use glucose test strips and a reflectometer to determine the concentration of glucose in whole blood. Some test strips use a glucose oxidase-colorimetric reaction. The test pad is impregnated with the enzymes glucose oxidase and peroxidase, and colour indicators. When whole blood is placed on the test pad, glucose is oxidized to gluconic acid and hydrogen peroxide with glucose oxidase acting as a catalyst. The hydrogen peroxide produced from the reaction oxidizes an oxygen acceptor in the presence of peroxidase to form a colour change. The intensity of the colour change is directly proportional to the amount of glucose in the blood sample and can be measured by a reflectometer.
When the glucose test strip is placed into the test chamber of the BGM, light shines on the reagent test pad and light is reflected. This reflected light is measured electronically and a blood glucose concentration value is displayed on the screen.
Absorbance photometry is another method which uses two wavelengths to measure glucose concentration rather than the single wavelength used by most reflectance photometry systems.
b) Glucose Dehydrogenase BGMs
Other BGMs use electrochemical methodologies. They measure the glucose amperometrically by measuring the current produced when glucose oxidase catalyzes the oxidation of glucose to gluconic acid or when glucose dehydrogenase catalyzes the oxidation of glucose to gluconolactone. Electrons are produced in this reaction and are transferred from the blood to the electrodes. The size of the resulting current is proportional to the concentration of glucose in the specimen and is converted to a blood glucose concentration value displayed on the monitor.
c) Glucose Hexokinase BGMs
Some BGMs use the reflectometric hexokinase method. When blood is applied to the reagent strip, glucose is phosphorylated to glucose-6-phosphate. This is later oxidized with concurrent reduction of NAD. The NADH formed is directly proportional to the amount of glucose present in the sample. Then the NADH, in the presence of another enzyme, reduces the dye and a coloured product is produced. When the test strip is inserted into the BGM, the photometer measures the light reflected and uses an algorithm to calculate the glucose concentration and displays the result.
Equipment needed:
Blood Glucose Monitor
BGM compatible glucose test strip
Lancet
Test for Blood Glucose
Two blood glucose tests should be carried out on the patient to measure:
a) The fasting blood glucose level (blood collected after an 8 to 10 hour fast)
b) Oral glucose tolerance test (OGTT). The patient must drink a glucose drink and another glucose test performed two hours after.
To carry out the blood glucose test
- Switch on the BGM.
- Prick the patients fingertip with the lancet and squeeze to push out a drop of blood.
- Touch the drop of blood to the reagent pad on the glucose test strip. Capillary action will draw the blood onto the pad.
- Insert the glucose test strip into the BGM and wait for the glucose concentration reading.
Blood Glucose Levels and Their Meanings
High levels of glucose usually indicate diabetes but other diseases and conditions can also result in a raised blood glucose. Below is a table showing the predictions that can be made for the resulting blood glucose concentration.
How to test for Glucose in Urine (glucose oxidase test)
The urine glucose test is performed by dipping a strip of urine test paper into a urine sample. The urine test paper is impregnated with two enzymes called glucose oxidase and peroxidase along with an oxygen acceptor chromagen.
When the strip is placed into the sample urine, any glucose in the urine is oxidized to gluconic acid and hydrogen peroxide with glucose oxidase acting as a catalyst. The hydrogen peroxide produced from the reaction oxidizes an oxygen acceptor in the presence of peroxidase to form a colour change. Early glucose oxidase tests used ortholidine as the oxygen acceptor. The oxidation of this chromagen resulted in a blue colour. Urine tests kits nowadays use chromagens such as potassium iodide to give a range of colours depending on the amount of glucose in the urine. The oxidation of potassium iodide results in colours ranging from blue-green to greenish-brown through brown and dark brown.
Equipment needed:
- Urine test strip
- A visual comparison colour chart for reading test results
- Clean, dry container for urine collection.
- Timer or watch capable of measuring accurately in seconds
Test Procedure:
- Collect urine specimen in a clean, dry container. Mix well immediately before testing. If urine specimens are not tested within 1-hour store at 2-4°C and bring to room temperature before testing.
- Remove strip from pouch for immediate use. Hold the plastic end of the strip. Completely immerse reagent area of the strip in urine sample and remove immediately to avoid dissolving out reagent area.
- Remove the strip slowly avoiding any spilling. Run the edge of the strip against the rim of the urine container to remove excess urine.
- Exactly 60 seconds after removing from the specimen, compare reagent area to the colour chart on the pouch. (Hold strip close to colour block and match carefully. Do not touch the colour block with the test area).
The higher the intensity of the colour brown, the higher the amount of glucose is contained in the urine.
Testing for urine glucose is one of the methods used to help with the diagnosis of disease, however it is highly inaccurate and unreliable compared to blood testing. Therefore, a blood glucose test will be performed to confirm or rule out diseases such as diabetes.
Two major problems with urine glucose testing are:
- Urine glucose testing doesn’t tell you about low glucose levels (below 180 mg/dl), since at lower levels glucose does not enter your urine
- Urine glucose readings change when the volume of your urine changes (dilution of the glucose concentration occurs when the volume of water/urine increases)
Abnormally high levels of urine glucose may indicate the following:
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- Drinking alcohol
- Drugs, such as acetaminophen and anabolic steroids
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Extensive
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- Insulin overdose
- Insulinomas (insulin-producing pancreatic tumors)
- Starvation
How to Test for Blood Cholesterol
Total cholesterol values reflect the total amount of cholesterol in the lipoproteins. Cholesterol can be measured using chemical or enzymatic methods. Whole blood, serum or plasma using either heparin or EDTA as anticoagulant can be used as specimens.
The colorimetric procedures that use strong acid containing reagents (e.g., Liebermann-Burchard) have now been replaced by enzymatic procedures even in the clinical laboratory. Nowadays, many cholesterol test systems use enzymatic methodology whereby enzyme reagent systems are coupled with various chromagens. The methodology is used in both manual and automated procedures. Compact portable analytical systems are now available and are able to measure whole blood without prior removal of red blood cells from the blood plasma using solid phase separators or filtrators that separate plasma from whole blood. These systems use enzymatic strip technology, much like the Blood Glucose Monitors described above and allow for quantitative measurement of cholesterol.
The Trinder reaction is the most common enzymatic method in cholesterol testing. This involves the breakdown of cholesterol esters to free cholesterol by the enzyme cholesterol esterase. The free cholesterol is then oxidized by Cholesterol oxidase, in the presence of oxygen, to form cholest-4-ene-3-one and hydrogen peroxide. In turn, the hydrogen peroxide reacts with phenol and 4-aminoantipyrine in the presence of peroxidase (POD) to form a quinoneimine dye. In other methods, phenol or other chromophores may be substituted. Enzymatic procedures may involve a catalase reaction sequence or amperometric measurement of either the oxygen consumed or that of hydrogen peroxide generation. The resulting colour is measured by reflectance photometry. The non-instrumented systems allow for visual determination of cholesterol by use of chromogens or indicator systems.
A cholesterol test is usually carried out after the individual has fasted overnight.
The patient should also be healthy because blood cholesterol is temporarily low during acute illness, immediately following a heart attack, or during stress (like from surgery or an accident). The cholesterol test should not be carried out until at least 6 weeks after any illness.
Equipment needed:
Blood Cholesterol Monitor
Blood Cholesterol Monitor compatible cholesterol test strip
Lancet
Test for Blood Cholesterol
To carry out the blood cholesterol test
- Switch on the Blood Cholesterol Monitor.
- Prick the patients fingertip with the lancet and squeeze to push out a drop of blood.
- Touch the drop of blood to the reagent pad on the cholesterol test strip. Capillary action will draw the blood onto the pad.
- Insert the glucose test strip into the Blood Cholesterol Monitor and wait for the cholesterol concentration reading.
Blood Cholesterol Levels and Their Meanings
The risk of a person developing heart disease is assessed using the blood cholesterol level along with other risk factors for heart disease e.g. high blood pressure and smoking. Doctors will decide whether or not a patient requires further treatment in the form of dietary changes or drugs to lower cholesterol level.
Total cholesterol results and their meanings are shown in the following table:
Abnormally high levels of blood cholesterol may indicate the following:
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• Biliary cirrhosis, which is scarring and blockage of the bile ducts
• diet high in , , calories, or
• Familial , a condition in which high blood lipids run in a family
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• High
• or an underactive thyroid gland
• Lack of exercise
• which is a kidney disease resulting in loss of protein in the urine
• Overweight or
• Uncontrolled
Abnormally low levels of cholesterol may indicate the following:
• or an overactive thyroid gland
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• or inadequate absorption of nutrients from the intestines
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There is some debate about whether very low cholesterol is bad. Low cholesterol is often seen when there is an existing problem like malnutrition, liver disease, or cancer. However there is no evidence that low cholesterol causes any of these problems.
The Cholesterol test is not always used to diagnose or monitor a disease but is also used to estimate the risk of developing heart disease. High blood cholesterol has been associated with artery hardening, heart disease and an increased risk of heart attacks. Therefore, cholesterol testing is considered a routine part of preventive health care.
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