What to know about fasting blood sugar?

Fasting blood sugar levels give vital clues about how a person’s body is managing blood sugar. Blood sugar tends to peak about an hour after eating and declines after that. High fasting blood sugar levels point to insulin resistance or diabetes, while abnormally low fasting blood sugar could be due to diabetes medications. Knowing when to test and what to look for can help keep people stay healthy, especially if they have diabetes or are at risk of developing the condition.

Fasting blood sugar levels

The body needs glucose for energy, and glucose comes from the food we eat. However, the body does not use all of this energy at once. Insulin makes it possible to store and release it as necessary. Following a meal, blood sugar levels rise, usually peaking about an hour after eating. How high blood sugar rises, and the precise timing of the peak depends on the person’s diet. Factors relating to food that can trigger significant rises include:

• eating large meals
• consuming glucose rich foods and drinks
• eating foods with simple carbohydrates, or carbs, such as bread and sweet snacks

As blood sugar rises, the pancreas releases insulin. Insulin lowers blood sugar, breaking it down so that the body can use it for energy or store it for later.

However, people who have diabetes have difficulties with insulin in one of two ways:

1. Those with type 1 diabetes do not produce enough insulin because their body attacks its insulin-producing cells.
2. Those with type 2 diabetes do not respond well to insulin in their body and, later, may not make enough insulin.

In both cases, the result is the same, with people experiencing high blood sugar levels and difficulty using glucose, or blood sugar. This means that fasting blood sugar depends on three factors:

• the contents of a person’s last meal
• the size of their previous meal
• their body’s ability to produce and respond to insulin

Blood sugar levels between meals offer a window into how the body manages sugar. High levels of fasting blood sugar suggest that the body has been unable to lower the levels of sugar in the blood. This points to either insulin resistance or inadequate insulin production and, in some cases, both.

What’s a HbA1c ?

A glycosylated haemoglobin test measures the amount of glucose (sugar) in your blood. The test is often called A1c, or sometimes HbA1c. It’s a simple blood test used to:

• Detect prediabetes - high sugar levels that can lead to diabetes, heart disease, and stroke.
• Diagnose diabetes.
• Tell how well a person with diabetes has been managing the disease.

How does the HbA1c test work?

HbA1c testing relies on haemoglobin. Haemoglobin is the part of the red blood cell that carries oxygen throughout the body. When you have glucose in your blood, it glycates (sticks) to haemoglobin. The more glucose in your blood, the more it sticks. And it can stay there for around three months, or about how long the average red blood cell lives. The HbA1c test measures the average amount of glucose that’s been attached to hemoglobin over time. So the HbA1c test provides more information about blood sugar over a longer period of time.

When is a HbA1c test needed?

If you have diabetes, you should have a HbA1c test two to four times a year to see how you’re managing it. Your physician or healthcare team will advise on exactly how often you should get tested.
If you haven’t gotten diagnosed with diabetes, a healthcare provider may order an HbA1c test if you have symptoms of the condition. These symptoms include:

• Blurry vision.
• Fatigue, or feeling tired all the time.
• Increased urination (peeing).
• Unusual thirst.

You may also get an HbA1c test if you’re at risk for diabetes. Risk factors include:

• Extra weight or obesity.
• Family history of diabetes.
• Lack of activity or exercise.
• History of heart disease.
• Hypertension (High Blood Pressure).
• Older age.

Complete Blood Count (CBC)

• Complete Blood Count can provide a quick snapshot of your overall health. A CBC is part of a routine physical exam.
• A CBC is a blood test that measures red blood cells, white blood cells, and blood platelets (cells that help your blood clot). It is one of the most common tests.

Other reasons your doctor may order a CBC can include:

If you are ill and have a fever or if he or she suspects any kind of infection.
If you are tired or are losing weight without trying.
If you have any sign of cancer, including general weakness, bruising, or bleeding.
If you have a condition that requires you to take daily medication, your doctor may order a CBC regularly to make sure your blood counts remain consistent.

These are some of the health problems that can be identified by a CBC:

• Anemia (low iron)
• Autoimmune disorders
• Bone marrow problems
• Cancer
• Dehydration
• Heart disease
• Infection
• Inflammation
• Vitamin and mineral deficiencies

Lipid profile

Lipid profile or lipid panel is a panel of blood tests that serves as an initial screening tool for abnormalities in lipids, such as cholesterol and triglycerides.

This test may be measured any time of the day without fasting. However, if the test is drawn as part of a total lipid profile, it requires a 12-hour fast (no food or drink, except water). For the most accurate results, wait at least two months after a heart attack, surgery, infection, injury, or pregnancy to check cholesterol levels.

Cholesterol is a type of fat, found in your blood. It is produced by your body and also comes from the foods you eat (animal products). Cholesterol is needed by your body to maintain the health of your cells. Too much cholesterol leads to coronary artery disease. Your blood cholesterol level is related to the foods you eat or to genetic conditions (passed down from other generations of family members).

High Density Lipoprotein (HDL) "Good cholesterol"

HDL is a lipoprotein (a combination of fat and protein) found in the blood. It is called "good" cholesterol because it removes excess cholesterol from the blood and takes it to the liver. A high HDL level is related to a lower risk of heart and blood vessel disease.

Low Density Lipoprotein (LDL) "Bad cholesterol"

LDL is a lipoprotein (a combination of fat and protein) found in the blood. It is called "bad" cholesterol because it picks up cholesterol from the blood and takes it to the cells. A high LDL level is related to a higher risk of heart and blood vessel disease.

Triglycerides (TG)

Triglycerides are a type of fat found in the blood. The blood level of this type of fat is most affected by the foods you eat (such as sugar, fat, or alcohol) but can also be high due to being overweight, having thyroid or liver disease, and genetic conditions. High levels of triglycerides are related to a higher risk of heart and blood vessel disease.

Who should get a cholesterol test?

According to the National Heart, Lung, and Blood Institute (NHLBI), a person's first cholesterol screening should occur between the ages of 9 and 11 and then be repeated every five years after that.The NHLBI recommends that cholesterol screenings occur every 1 to 2 years for men ages 45 to 65 and for women ages 55 to 65. People over 65 should receive cholesterol tests annually.More frequent testing might be needed if your initial test results were abnormal or if you already have coronary artery disease, you're taking cholesterol-lowering medications or you're at higher risk of coronary artery disease because you:

• Have a family history of high cholesterol or heart attacks
• Are overweight
• Are physically inactive
• Have diabetes
• Eat an unhealthy diet
• Smoke cigarettes

People undergoing treatment for high cholesterol require regular cholesterol testing to monitor the effectiveness of their treatments.

Liver function tests are blood tests used to help diagnose and monitor liver disease or damage. The tests measure the levels of certain enzymes and proteins in your blood.

Some of these tests measure how well the liver is performing its normal functions of producing protein and clearing bilirubin, a blood waste product. Other liver function tests measure enzymes that liver cells release in response to damage or disease.

• Screen for liver infections, such as hepatitis
• Monitor the progression of a disease, such as viral or alcoholic hepatitis, and determine how well a treatment is working
• Measure the severity of a disease, particularly scarring of the liver (cirrhosis)
• Monitor possible side effects of medications

Alanine transaminase (ALT). ALT is an enzyme found in the liver that helps convert proteins into energy for the liver cells. When the liver is damaged, ALT is released into the bloodstream and levels increase.

Aspartate transaminase (AST). AST is an enzyme that helps metabolize amino acids. Like ALT, AST is normally present in blood at low levels. An increase in AST levels may indicate liver damage, disease or muscle damage.

Alkaline phosphatase (ALP). ALP is an enzyme found in the liver and bone and is important for breaking down proteins. Higher-than-normal levels of ALP may indicate liver damage or disease, such as a blocked bile duct, or certain bone diseases.

Albumin and total protein. Albumin is one of several proteins made in the liver. Your body needs these proteins to fight infections and to perform other functions. Lower-than-normal levels of albumin and total protein may indicate liver damage or disease.

Bilirubin. Bilirubin is a substance produced during the normal breakdown of red blood cells. Bilirubin passes through the liver and is excreted in stool. Elevated levels of bilirubin (jaundice) might indicate liver damage or disease or certain types of anemia.

Gamma-glutamyltransferase (GGT). GGT is an enzyme in the blood. Higher-than-normal levels may indicate liver or bile duct damage

Purpose of the test

The purpose of a renal panel test is to find or rule out potential kidney impairment or disease. Depending on the circumstances, it may be used for diagnosis, screening, or monitoring.

Diagnosis is the identification of a health problem after signs or symptoms have started. A renal panel may be ordered if the doctor believes that symptoms could be related to an issue affecting the kidneys.

Screening is testing with the goal of early detection of a problem. Screening tests are done before any symptoms have occurred. For people who are at higher risk of developing kidney disease, a renal panel may be prescribed to try to reveal problems at an earlier stage.

Monitoring is how a patient’s situation can be tracked over time. Repeat testing with a renal panel can show if the condition of the kidneys is getting better or worse. This monitoring may be done after treatment for kidney disease. It can also be used to watch for changes to kidney function when taking medications that can cause kidney impairment.

What does the test measure?

A renal panel includes multiple measurements. However, not all renal panel tests are exactly the same. The components can depend on the laboratory or the measurements requested by the doctor prescribing the test.

The most common components tested in most renal panels include:

• Glucose: Also known as blood sugar, glucose provides energy for the body. Excess glucose in the blood, though, can be a sign of metabolic problems like diabetes.
• Phosphorus: Phosphorus is an essential mineral for your bones, teeth, nervous system, and muscles. Phosphorus comes primarily from the foods and drinks that you consume.
• Calcium: Calcium is a mineral that is vital for the bones, muscles, cardiovascular system, and nervous system. The main source of calcium is your diet, and the body stores calcium in the bones.
• Potassium: Potassium is a type of electrolyte. Electrolytes are minerals that enable acid-base balance, healthy fluid levels, and proper functioning of muscles and nerves. Potassium comes from your diet and is found throughout the body.
• Sodium: Sodium is another electrolyte that comes from your diet, and the amount of sodium in the body is largely controlled by the kidneys.
• Chloride: Chloride is an electrolyte that works in conjunction with other electrolytes to carry out various functions, including preserving a healthy balance of fluids.
• Bicarbonate: Bicarbonate is another electrolyte. Levels of bicarbonate help assess the amount of carbon dioxide (CO2) in your blood.
• Albumin: Albumin is a protein that is produced in the liver and found in the blood. It carries important substances through the body and helps maintain the proper pressure in the blood vessels so that fluids do not leak out of the blood.
• Creatinine: Creatinine is a waste byproduct that is consistently formed as a result of normal muscle activity. The kidneys remove creatinine from the blood so that it can be carried out of the body in urine.
• Blood urea nitrogen (BUN): Urea nitrogen, sometimes just called urea, is a waste product from protein activity. Like creatinine, it is removed from the blood by the kidneys and cleared from the body in urine.

Other measurements that may also include in a renal panel include:

• Anion gap: The anion gap is a comparison of different electrolytes. Specific electrolytes can be positively or negatively charged, and this test assesses the balance between the two types. This measurement helps determine if you have too much or too little acid in your blood.
• Estimated glomerular filtration rate (eGFR): The eGFR is an evaluation of kidney function. Glomeruli are tiny filters in the kidneys, and the eGFR is a calculation of how much blood they are filtering every minute. There are different ways to calculate eGFR, but most tests use a special formula based on your creatinine level.
• Total protein: There are several kinds of proteins that can be found in the blood, and total protein is a count of all of them. These proteins include albumin and multiple types of globulins, which are made by the immune system.
• BUN-to-creatinine ratio: In some cases, comparing the amounts of the waste products BUN and creatinine can provide information about whether abnormal levels are being caused by problems in the kidneys or another part of the body.

When should I get a renal panel test?

A renal panel test can be used in a range of circumstances, and the doctor may include specific measurements depending on your situation. As a diagnostic test, a renal panel is most frequently used when you have symptoms that could be explained by a kidney problem. Examples of symptoms that can be tied to kidney impairment or disease include:

• Urinary changes including changes to the frequency, quantity, or appearance of your urine
• Unexplained swelling, especially in your arms, hands, legs, and/or face
• Itching
• Loss of concentration
• Appetite changes
• Difficulty breathing
• Nausea and/or vomiting
• Fatigue
• Muscle cramps or pain

A test like the renal panel may also be used for diagnosis when you have general symptoms without a clear cause or are being evaluated in urgent care or emergency setting.

As a screening test, the renal panel or other tests of kidney health are most often prescribed if you have certain risk factors for kidney disease. Some of these risk factors include high blood pressure, diabetes, and a family history of kidney disease.

For people with an elevated risk of kidney problems, screening with a renal panel may be part of normal health checkups. Screening of this type is not standard in people who do not have risk factors.

A renal panel can be used as a monitoring test if you have had kidney problems in the past or have already had an abnormal renal panel test. If you are receiving treatment for kidney injury or disease, a renal panel may be used to gauge your response to that therapy.

If you are going to have a medical procedure or take any drugs that can impair kidney function, your doctor may prescribe a renal panel before and/or after to monitor for possible kidney-related side effects.

How to get tested

In general, a renal panel is ordered by a doctor, and the blood sample is drawn in a medical office, laboratory, or hospital.

Before the test

• For many renal panel tests, you will need to fast for 8 to 12 hours before your blood draw.
• During this time, you can only drink water. You cannot eat any food or drink other beverages.
• However, because the exact components of a renal panel test can vary, you should ask your doctor about whether you need to fast beforehand.
• You should also tell your doctor about any prescriptions, over-the-counter medications, or supplements that you take.
• If any of these can affect the test, your doctor may ask you to temporarily stop taking them before the test.

During the test

• When it’s time for your test, you will be seated while a technician or nurse prepares to draw your blood.
• They will tie a band around your upper arm to enhance blood flow lower in your arm.
• An antiseptic wipe will be used to clean the skin around your vein, and then a needle will be inserted into the vein.
• The needle is used to withdraw a vial of blood and is then removed from your arm.
• This type of blood draw is a routine procedure that normally lasts only a few minutes.
• You may experience some brief pain or a stinging sensation during the test.

After the test

• When the needle is removed from your arm, a bandage or cotton swab will be used to stop any further bleeding.
• You may experience some soreness or bruising, but these effects are rarely long-lasting.
• If you are required to fast, you may want to bring a snack immediately after the test.
• Once your blood draw is finished, you can return to most normal activities, including driving.

What is a TSH(Thyroid-stimulating hormone) test ?

TSH stands for thyroid-stimulating hormone. A TSH test is a blood test that measures this hormone. The thyroid is a small, butterfly-shaped gland located near your throat. Your thyroid makes hormones that regulate the way your body uses energy. It also plays an important role in regulating your weight, body temperature, muscle strength, and even your mood. TSH is made in a gland in the brain called the pituitary. When thyroid levels in your body are low, the pituitary gland makes more TSH. When thyroid levels are high, the pituitary gland makes less TSH. TSH levels that are too high or too low can indicate your thyroid isn't working correctly.

Other names: thyrotropin test

What is it used for ?

A TSH test is used to find out how well the thyroid is working.

Why do I need a TSH test?

You may need a TSH test if you have symptoms of too much thyroid hormone in your blood (hyperthyroidism), or too little thyroid hormone (hypothyroidism).
Symptoms of hyperthyroidism, also known as overactive thyroid, include:

• Anxiety
• Weight loss
• Tremors in the hands
• Increased heart rate
• Puffiness
• Bulging of the eyes
• Difficulty sleeping

Symptoms of hypothyroidism, also known as underactive thyroid, include:

• Weight gain
• Tiredness
• Hair loss
• Low tolerance for cold temperatures
• Irregular menstrual periods
• Constipation

What happens during a TSH test?

A health care professional will take a blood sample from a vein in your arm, using a small needle. After the needle is inserted, a small amount of blood will be collected into a test tube or vial. You may feel a little sting when the needle goes in or out. This usually takes less than five minutes.

Will I need to do anything to prepare for the test?

You don't need any special preparations for a TSH blood test. If your health care provider has ordered other blood tests, you may need to fast (not eat or drink) for several hours before the test. Your health care provider will let you know if there are any special instructions to follow.

Are there any risks to the test?

There is very little risk to having a blood test. You may have slight pain or bruise at the spot where the needle was put in, but most symptoms go away quickly.

What is a Calcium Test?

Definition:

Serum calcium is a blood test to measure the amount of calcium in the blood. Serum calcium is usually measured to screen for or monitor bone diseases or calcium-regulation disorders (diseases of the parathyroid gland or kidneys).

Alternative Names: Ca+2; Calcium - serum; Ca++

How the test is performed ?

Blood is drawn from a vein, usually from the inside of the elbow or the back of the hand. The puncture site is cleaned with antiseptic. An elastic band is placed around the upper arm to apply pressure and cause the vein to swell with blood.

A needle is inserted into the vein, and the blood is collected in an air-tight vial or a syringe. During the procedure, the band is removed to restore circulation. Once the blood has been collected, the needle is removed, and the puncture site is covered to stop any bleeding.

For an infant or young child, the area is cleansed with antiseptic and punctured with a sharp needle or a lancet. The blood may be collected in a pipette (small glass tube), on a slide, onto a test strip, or into a small container. A bandage may be applied to the puncture site if there is any bleeding.

How to prepare for the test ?

Drugs that can cause increased measurements in this test include calcium salts (for example, in nutritional supplements or antacids), vitamin D, lithium, thiazide diuretics, and thyroxine. Consult your health care provider regarding the need to discontinue drugs that may affect this test.

How the test will feel

When the needle is inserted to draw blood, some people feel moderate pain, while others feel only a prick or stinging sensation. Afterward, there may be some throbbing.

Why the test is performed

All cells require calcium to function. Calcium is especially important in the structure of bones and in neuromuscular (nerves and muscles) activity. A deficiency of calcium in body fluids causes hyperexcitable nerves and muscles. Excess calcium has the opposite effect.

Normal Values:

Normal values range from 8.5 to 10.2 mg/dL. Normal value ranges may vary slightly among different laboratories.

What abnormal results mean:

Abnormal results indicate the following:

Higher-than-normal levels may indicate:

• Hyperparathyroidism
• Metastatic bone tumor
• Milk-alkali syndrome
• Multiple myeloma
• Paget's disease
• Sarcoidosis
• Tumors producing a PTH-like substance
• Vitamin D intoxication
• Excessive calcium intake
• Prolonged immobilization
• Hyperthyroidism (overactive thyroid gland)
• Addison's disease (underactive adrenal gland)
• Thiazide diuretics
• Lithium
• HIV/AIDS

Lower-than-normal levels may indicate:

• Hypoparathyroidism
• Malabsorption (inadequate absorption of nutrients from the intestinal tract)
• Osteomalacia
• Pancreatitis
• Renal failure
• Rickets and vitamin D deficiency
• Liver disease (decreased albumin production)
• Low serum magnesium

Additional conditions under which the test may be performed:

• Delirium
• Dementia
• Multiple endocrine neoplasia (MEN) II
• Multiple endocrine neoplasia (MEN) I
• Renal cell carcinoma
• Secondary hyperparathyroidism

What the risks are ?

• Excessive bleeding
• Fainting or feeling lightheaded
• Hematoma (blood accumulating under the skin)
• Infection (a slight risk any time the skin is broken)
• Multiple punctures to locate veins

Special considerations:

Drinking too much milk or taking too much vitamin D as a dietary supplement can increase calcium levels.
Veins and arteries vary in size from one patient to another and from one side of the body to the other.
Obtaining a blood sample from some people may be more difficult than from others.

What are iron tests?

Iron tests measure different substances in the blood to check iron levels in your body. Iron is a mineral that's essential for making red blood cells. Red blood cells carry oxygen from your lungs to the rest of your body. Iron is also important for healthy muscles, bone marrow, and organ function. Iron levels that are too low or too high can cause serious health problems.

Different types of iron tests include:

• Serum iron test, which measures the amount of iron in the blood
• Transferrin test, which measures transferrin, a protein that moves iron throughout the body
• Total iron-binding capacity (TIBC), which measures how well iron attaches to transferrin and other proteins in the blood
• Ferritin blood test, which measures how much iron is stored in the body

Some or all of these tests are often ordered at the same time.

Other names: Fe tests, iron indices

What are they used for?

Iron tests are most often used to:

• Check if your iron levels are too low, a sign of anemia
• Diagnose different types of anemia
• Check if your iron levels are too high, which could be a sign of hemochromatosis. This is a rare genetic disorder that causes too much iron to build up in the body.
• See if treatments for iron deficiency (low iron levels) or excess iron (high iron levels) are working

Why do I need an iron test?

You may need testing if you have symptoms of iron levels that are too low or too high.

Symptoms of iron levels that are too low include:

• Pale skin
• Fatigue
• Weakness
• Dizziness
• Shortness of breath
• Rapid heartbeat

Symptoms of iron levels that are too high include:

• Joint pain
• Abdominal pain
• Lack of energy
• Weight loss

What happens during an iron test?

A health care professional will take a blood sample from a vein in your arm, using a small needle. After the needle is inserted, a small amount of blood will be collected into a test tube or vial. You may feel a little sting when the needle goes in or out. This usually takes less than five minutes.

Will I need to do anything to prepare for the test?

Your health care provider may ask you to fast (not eat or drink) for 12 hours before your test. The test is usually done in the morning. If you have any questions about how to prepare for your test, talk to your health care provider.

Are there any risks to iron tests?

There is very little risk to having a blood test. You may have slight pain or bruise at the spot where the needle was put in, but most symptoms go away quickly.