Dr. Amaya Stiedemann DVM

When Your Blood Sugar Is Too High or Too Low

Sometimes, no matter how hard you try to keep your blood sugar in the range your doctor has advised, it can be too high or too low. Blood sugar that is too high or too low can make you very sick. Here’s how to handle these emergencies.

What You Need to Know about High Blood Sugar

If your blood sugar stays over 240, it is too high. High blood sugar usually comes on slowly. It happens when you don’t have enough insulin in your body. High blood sugar can happen if you miss taking your diabetes medicine, eat too much, or don’t get enough exercise. Sometimes, medicines you take for other problems may cause high blood sugar. Be sure to tell your doctor about other medicines you take.

This chart shows the ranges of blood sugar.

Having an infection or being sick or under stress can also make your blood sugar too high. That is why it is very important to test your blood and keep taking your medicine (insulin or diabetes pills) when you have an infection or are sick.

Your blood sugar may be too high if you are very thirsty and tired, have blurry vision, are losing weight fast, and have to go to the bathroom often. Very high blood sugar may make you feel sick to your stomach, faint, or throw up. It can cause you to lose too much fluid from your body.

Testing your blood sugar often, especially when you are sick, will warn you that your blood sugar may be rising too high. If your blood sugar stays over 300 when you check it two times in a row, call your doctor. You may need a change in your insulin shots or diabetes pills, or a change in your meal plan.

If you are not sick and do not have ketones in your urine, going for a slow walk or some other easy exercise may lower your blood sugar.

What You Need to Know about Low Blood Sugar

If your blood sugar drops too low, you can have a low blood sugar reaction, called hypoglycemia. A low blood sugar reaction can come on fast. It is caused by taking too much insulin, missing a meal, delaying a meal, exercising too much, or drinking too much alcohol. Sometimes, medicines you take for other health problems can cause blood sugar to drop.


A low blood sugar reaction can make you feel shaky, mixed up, unhappy, hungry, or tired. You may sweat a lot or get a headache. Your legs may shake. If your blood sugar drops lower, you can get very confused, sleepy, or irritable, or you may pass out or have a seizure.

Treat low blood sugar quickly. If you have signs of low blood sugar, eat or drink something that has sugar in it. Some things you can eat are hard candy, sugar-sweetened soda, orange juice, or a glass of milk. Special tablets or gel made of glucose (a form of sugar) can be used to treat low blood sugar. You can buy these in a drug store. Always have some of these items handy at home or with you when you go out in case your blood sugar drops too low. After treating a low blood sugar reaction, eat a small snack like half a sandwich, a glass of milk, or some crackers if your next meal is more than 30 minutes away.

In case of a medical emergency, be sure that you carry medical identification (a tag or card) that says you have diabetes and lists the medicines you take. It should also give the name and telephone number of your doctor. Tell your family, friends, teachers, or other people you see often about the signs of low blood sugar. Explain how to treat it. You may need their help some day.

You can prevent most low blood sugar reactions by eating your meals on time, taking your diabetes medicine, and testing your blood sugar often. Testing your blood will show if your sugar level is going down. You can then take steps, like eating some fruit, crackers, or other snack, to raise your blood sugar level.

Action Steps…

If You Use Insulin

  • Tell your doctor if you have low blood sugar reactions often, especially if they happen at the same time of day or night.
  • Tell your doctor if you have passed out from low blood sugar or if you ever needed someone’s help.
  • Ask your doctor about “glucagon.” Glucagon is a medicine to raise blood sugar. If you pass out from low blood sugar, someone should call “911” emergency and give you a glucagon shot.


If You Don’t Use Insulin

  • Be sure to tell your doctor about other medicines you may be taking.
  • If you take diabetes pills you can also have low blood sugar reactions. The doctor may need to make a change in your medicine or eating plan. (If you don’t take pills or insulin, you don’t have to worry about low blood sugar reactions.)

Always be prepared for a low blood sugar reaction. Keep a snack handy. Ask your doctor or diabetes educator for a list of snacks to treat low blood sugar.

Information for Your Doctor about This Document

Blood glucose values and other management guidelines cited in this document are based on recommendations from:

  • American Association of Diabetes Educators
  • American Diabetes Association
  • Centers for Disease Control and Prevention, Division of Diabetes Translation
  • Diabetes program at the Warren Grant Magnuson Clinical Center, National Institutes of Health (NIH).

Recommendations for improving blood glucose control are based on the Diabetes Control and Complications Trial (DCCT), a 10-year clinical study of insulin-dependent diabetes sponsored by the National Institute of Diabetes and Digestive and Kidney Diseases, NIH. The DCCT showed that volunteers who intensively managed their diabetes reduced their risk of eye disease by 76 percent, kidney disease by 50 percent, and nerve disease by 60 percent.


Blood Glucose Test: Preparation, Procedure, and More

A blood glucose test measures the amount of glucose in your blood. Glucose, a type of simple sugar, is your body’s main source of energy. Your body converts the carbohydrates you eat into glucose.

Glucose testing is primarily done for people with type 1 diabetes, type 2 diabetes, and gestational diabetes. Diabetes is a condition that causes your blood glucose levels to rise.

The amount of sugar in your blood is usually controlled by a hormone called insulin. However, if you have diabetes, your body either doesn’t make enough insulin or the insulin produced doesn’t work properly. This causes sugar to build up in your blood. Increased levels of blood sugar can lead to severe organ damage if left untreated.

In some cases, blood glucose testing may also be used to test for hypoglycemia. This condition occurs when the levels of glucose in your blood are too low.

Type 1 diabetes is usually diagnosed in children and teenagers whose bodies aren’t able to produce enough insulin. It’s a chronic or long-term condition that requires continuous treatment. Late-onset type 1 diabetes has been shown to affect people between the ages of 30 and 40.

Type 2 diabetes is usually diagnosed in overweight and obese adults, but it can develop in younger people as well. This condition occurs when your body doesn’t make enough insulin or when the insulin you produce doesn’t work properly. The impact of type 2 diabetes may be reduced through weight loss and healthy eating.

Gestational diabetes occurs if you develop diabetes while you’re pregnant. Gestational diabetes usually goes away after you give birth.

After receiving a diagnosis of diabetes, you may have to get blood glucose tests to determine if your condition is being managed well. A high glucose level in a person with diabetes may mean that your diabetes isn’t being managed correctly.

Other possible causes of high blood glucose levels include:

  • hyperthyroidism, or overactive thyroid
  • pancreatitis, or inflammation of your pancreas
  • pancreatic cancer
  • prediabetes, which happens when you’re at increased risk of developing type 2 diabetes
  • stress to the body from illness, trauma, or surgery
  • medications such as steroids

In rare cases, high blood glucose levels could be a sign of a hormonal disorder called acromegaly, or Cushing syndrome, which occurs when your body produces too much cortisol.

It’s also possible to have levels of blood glucose that are too low. However, this isn’t as common. Low blood glucose levels, or hypoglycemia, may be caused by:

  • insulin overuse
  • starvation
  • hypopituitarism, or underactive pituitary gland
  • hypothyroidism, or underactive thyroid
  • Addison’s disease, which is characterized by low levels of cortisol
  • alcohol abuse
  • liver disease
  • insulinoma, which is a type of pancreatic tumor
  • Kidney disease

Blood glucose tests are either random or fasting tests.

For a fasting blood glucose test, you can’t eat or drink anything but water for eight hours before your test. You may want to schedule a fasting glucose test first thing in the morning so you don’t have to fast during the day. You may eat and drink before a random glucose test.

Fasting tests are more common because they provide more accurate results and are easier to interpret.

Before your test, tell your doctor about the medications you’re taking, including prescriptions, over-the-counter drugs, and herbal supplements. Certain medications can affect blood glucose levels. Your doctor may ask you to stop taking a particular medication or to change the dosage before your test temporarily.

Medications that can affect your blood glucose levels include:

  • corticosteroids
  • diuretics
  • birth control pills
  • hormone therapy
  • aspirin (Bufferin)
  • antipsychotics
  • lithium
  • epinephrine (Adrenalin)
  • tricyclic antidepressants
  • monoamine oxidase inhibitors (MAOIs)
  • ·phenytoin
  • sulfonylurea medications

Severe stress can also cause a temporary increase in your blood glucose and is usually due to one or more of these factors:

  • surgery
  • trauma
  • stroke
  • heart attack

You should tell your doctor if you’ve recently had any of these.

A blood sample can most likely be collected with a very simple prick to a finger. If you need other tests, your doctor may require a blood draw from a vein.

Before drawing blood, the healthcare provider performing the draw cleans the area with an antiseptic to kill any germs. They next tie an elastic band around your upper arm, causing your veins to swell with blood. Once a vein is found, they insert a sterile needle into it. Your blood is then drawn into a tube attached to the needle.

You may feel slight to moderate pain when the needle goes in, but you can reduce the pain by relaxing your arm.

When they’re finished drawing blood, the healthcare provider removes the needle and places a bandage over the puncture site. Pressure will be applied to the puncture site for a few minutes to prevent bruising.

The sample of blood is then sent to a lab for testing. Your doctor will follow up with you to discuss the results.

There’s a very low chance that you’ll experience a problem during or after a blood test. The possible risks are the same as those associated with all blood tests. These risks include:

  • multiple puncture wounds if it’s difficult to find a vein
  • excessive bleeding
  • lightheadedness or fainting
  • hematoma, or blood collecting under your skin
  • infection

Normal results

The implications of your results will depend on the type of blood glucose test used. For a fasting test, a normal blood glucose level is between 70 and 100 milligrams per deciliter (mg/dL). For a random blood glucose test, a normal level is usually under 125 mg/dL. However, the exact level will depend on when you last ate.

Abnormal results

If you had a fasting blood glucose test, the following results are abnormal and indicate you may have either prediabetes or diabetes:

  • A blood glucose level of 100–125 mg/dL indicates that you have prediabetes.
  • A blood glucose level of 126 mg/dL and higher indicates that you have diabetes.

If you had a random blood glucose test, the following results are abnormal and indicate you may have either prediabetes or diabetes:

  • A blood glucose level of 140–199 mg/dL indicates that you may have prediabetes.
  • A blood glucose level of 200 mg/dL and higher indicates that you likely have diabetes.

If your random blood glucose test results are abnormal, your doctor will probably order a fasting blood glucose test to confirm the diagnosis or another test such as an Hgba1c.

If you’re diagnosed with prediabetes or diabetes, you can find more information and additional resources at http://healthline.com/health/diabetes.


Is 3.7 too low for blood glucose?

Most people have hypoglycemic feelings when under 3.9 mmol/L ( 70 mg/dl ). A diabetic must be concerned about low glucose levels because a diabetic often injects insulin or takes medication to lower their blood glucose and as the cannot reduce a dose after it has been injected or swallowed, lowering glucose levels can be very dangerous hence the jelly bean advice from your friend cause a diabetic must correct the situation manually. A non-diabetic who wouldn’t be on insulin or medications for diabetes has little to fear from such symptoms but a quick snack should resolve the symptoms promptly.

Normally, a glucose test would be done fasting and done two hours after a meal ( postprandial ). The postprandial is considered normal if it’s under 7.8 mmol/L ( 140 mg/dl ) and diabetic when it’s 11.1 mmol/L ( 200 mg/dl ) or higher. As it’s doubtful that you took a reading at a useful time, you should see your Doctor and get a HbA1c test done.

As your measurement of 3.7 mmol/L was 30 minutes after your meal, you must’ve had a very high glycemic meal. The insulin your body produces lasts longer than very sugary food. You should divide your meals down into smaller, more frequent meals, select lower glycemic index alternatives and even replace or omit some cards. However 8.9 mmol/L is a little high, you may be prediabetic.


Blood Test Results – Your Complete Guide to Understanding Numbers

If you’re like most of my patients, you’ve probably looked over the alphabet soup of acronyms and abbreviations in your blood test results and wondered what it all means. So to empower my readers, here is a simplified guide to understanding your blood test results. If you’re interested in playing a more active role in your medical care — something I strongly recommend — then I suggest you save this! The next time you have blood work done; you’ll be able to read the results like a pro!

Blood tests, sometimes called blood panels, are one of a physician’s most basic tools. Not that long ago, doctors diagnosed patients through observation and the patients’ answers to questions. Today, we have a wide range of testing options to choose from, with blood tests being among the most basic.

Blood tests allow a doctor to see a detailed analysis of any disease markers, the nutrients and waste products in your blood as well as how various organs (e.g., kidneys and liver) are functioning. Below, I’ve explained some of the commonly measured indicators of health.

During a physical examination, your doctor will often draw blood for chemistry and complete blood count (CBC) tests as well as a lipid profile, which measures cholesterol and related elements. Here is a brief explanation of the abbreviations used in measurements followed by descriptions of several common test components.

Deciphering Blood Test Measurements

Blood tests use the metric measurement system and abbreviations such as the following:

cmm cells per cubic millimeter

fL (femtoliter) fraction of one-millionth of a liter

g/dL grams per deciliter

IU/L international units per liter

mEq/L milliequivalent per liter

mg/dL milligrams per deciliter

mL milliliter

mmol/L millimoles per liter

ng/mL nanograms per milliliter

pg (picograms) one-trillionth of a gram

Chemistry Panel (or Metabolic Panel)

ALT (alanine aminotransferase)

Healthy range: 8 to 37 IU/L
This test looks at levels of the liver enzyme ALT. When all’s well with your liver, your score on this test should be within range. Anything higher may indicate liver damage.


Healthy range: 3.9 to 5.0 g/dL
A protein made by the liver, albumin levels can be an indicator of liver or kidney problems.

A/G ratio (albumin/globulin ratio) or total protein test

Healthy ratio: a bit over 1, favoring albumin
There are two types of protein your blood — albumin (see above) and globulin. The A/G ratio test compares levels of these proteins with one another. Elevated protein levels could indicate a health condition in need of attention.

Alkaline phosphatase

Healthy range: 44 to 147 IU/L
This enzyme is involved in both liver and bone, so elevations may indicate problems with the liver or bone-related disease.

AST (aspartate aminotransferase)

Healthy range: 10 to 34 IU/L
This enzyme is found in heart and liver tissue, so elevations suggest problems may be occurring in one or both of those areas.


Healthy range: 0.1 to 1.9 mg/dL
This provides information about liver and kidney functions, problems in bile ducts, and anemia.

BUN (blood urea nitrogen)

Healthy range: 10 to 20 mg/dL
This is another measure of kidney and liver functions. High values may indicate a problem with kidney function. A number of medications and a diet high in protein can also raise BUN levels.

BUN/creatinine ratio

Healthy ratio of BUN to creatinine: 10:1 to 20:1 (men and older individuals may be a bit higher)
This test shows if kidneys are eliminating waste properly. High levels of creatinine, a by-product of muscle contractions, are excreted through the kidneys and suggest reduced kidney function.


Healthy range: 9.0 to 10.5 mg/dL (the elderly typically score a bit lower)
Too much calcium in the bloodstream could indicate kidney problems; overly active thyroid or parathyroid glands; certain types of cancer, including lymphoma; problems with the pancreas; or a deficiency of vitamin D.


Healthy range: 98 to 106 mEq/L
This mineral is often measured as part of an electrolyte panel. A high-salt diet and/or certain medications are often responsible for elevations in chloride. Excess chloride may indicate an overly acidic environment in the body. It also could be a red flag for dehydration, multiple myeloma, kidney disorders, or adrenal gland dysfunction.


Healthy range: 0.5 to 1.1 mg/dL for women; 0.6 to 1.2 mg/dL for men (the elderly may be slightly lower)
The kidneys process this waste product, so elevations could indicate a problem with kidney function.

Fasting glucose (blood sugar)

Healthy range: 70 to 99 mg/dL for the average adult (the elderly tend to score higher even when they are healthy)
Blood sugar levels can be affected by food or beverages you have ingested recently, your current stress levels, medications you may be taking, and the time of day. The fasting blood sugar test is done after at least 6 hours without food or drink other than water.


Healthy range: 2.4 to 4.1 mg/dL
Phosphorus plays an important role in bone health and is related to calcium levels. Too much phosphorus could indicate a problem with kidneys or the parathyroid gland. Alcohol abuse, long-term antacid use, excessive intake of diuretics or vitamin D, and malnutrition can also elevate phosphorus levels.


Healthy range: 3.7 to 5.2 mEq/L
This mineral is essential for relaying nerve impulses, maintaining proper muscle functions, and regulating heartbeats. Diuretics, drugs that are often taken for high blood pressure, can cause low levels of potassium.


Healthy range: 135 to 145 mEq/L
Another member of the electrolyte family, the mineral sodium helps your body balance water levels and helps with nerve impulses and muscle contractions. Irregularities in sodium levels may indicate dehydration; disorders of the adrenal glands; excessive intake of salt, corticosteroids, or pain-relieving medications; or problems with the liver or kidneys.

Lipid Panel (or Lipid Profile)

The lipid panel is a collection of tests measuring different types of cholesterol and triglycerides (fats) in your bloodstream.

Total cholesterol
General rules (best to worst):

Healthy Below 200 mg/dL (below 5.18 mmol/L)

Borderline high 200 to 239 mg/dL (5.2 to 6.2 mmol/L)

High Above 240 mg/dL (above 6.2 mmol/L)

This test measures combined levels of both LDL (bad) and HDL (good) cholesterol. The test may be done simply to record an individual’s cholesterol levels or for comparison purposes (e.g., to determine if cholesterol-lowering medications or nutrients are working).


Healthy range: 40 to 160 mg/dL
These fats are found in the bloodstream and may contribute to heart disease and other health problems.

HDL (Good) cholesterol
General rules:

Best Above 60 mg/dL

Good 50 to 60 mg/dL

Poor Below 40 mg/dL for men; below 50 mg/dL for women

Also known as good cholesterol, HDL (high-density lipoprotein) protects against heart disease. Low scores are risk factors for heart disease.

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LDL (Bad) cholesterol
General rules (best to worst):

Optimal Below 100 mg/dL

Near optimal 100 to 129 mg/dL

Borderline high 130 to 159 mg/dL

High 160 to 189 mg/dL

Very high Above 189 mg/dL

Also known as bad cholesterol, LDL (low-density lipoprotein) is the substance that clogs arteries and is linked to heart disease.

Total cholesterol/HDL ratio
American Heart Association guidelines:

Optimal Ratio of 3.5 to 1

Healthy Ratio of 5 to 1 or lower

This ratio is another way of checking your risk of heart disease. It is determined by dividing your HDL cholesterol level into total cholesterol. But don’t worry about the math — the lab normally does the calculation, so your doctor will simply tell you what the ratio is.

Complete Blood Count (CBC)

The CBC test examines cellular elements in the blood, including red blood cells, various white blood cells, and platelets. Here is a list of the components that are normally measured, along with typical values. If your doctor says you’re fine but your tests results are somewhat different from the range shown here, don’t be alarmed. Some labs interpret test results a bit differently from others, so don’t consider these figures absolutes.

WBC (white blood cell) leukocyte count

Normal range: 4,300 to 10,800 cmm
White blood cells help fight infections, so a high white blood cell count could be helpful for identifying infections. It may also indicate leukemia, which can cause an increase in the number of white blood cells. On the other hand, too few white blood cells could be caused by certain medications or health disorders.

WBC (white blood cell) differential count
Normal range:

Neutrophils 40% to 60% of the total

Lymphocytes 20% to 40%

Monocytes 2% to 8%

Eosinophils 1% to 4%

Basophils 0.5% to 1%

This test measures the numbers, shapes, and sizes of various types of white blood cells listed above. The WBC differential count also shows if the numbers of different cells are in proper proportion to each other. Irregularities in this test could signal an infection, inflammation, autoimmune disorders, anemia, or other health concerns.

RBC (red blood cell) erythrocyte count

Normal range: 4.2 to 5.9 million cmm
We have millions of red blood cells in our bodies, and this test measures the number of RBCs in a specific amount of blood. It helps us determine the total number of RBCs and gives us an idea of their lifespan, but it does not indicate where problems originate. So if there are irregularities, other tests will be required.

Hematocrit (Hct)

Normal range: 45% to 52% for men; 37% to 48% for women
Useful for diagnosing anemia, this test determines how much of the total blood volume in the body consists of red blood cells.

Hemoglobin (Hgb)

Normal range: 13 to 18 g/dL for men; 12 to 16 g/dL for women
Red blood cells contain hemoglobin, which makes blood bright red. More importantly, hemoglobin delivers oxygen from the lungs to the entire body; then it returns to the lungs with carbon dioxide, which we exhale. Healthy hemoglobin levels vary by gender. Low levels of hemoglobin may indicate anemia.

Mean corpuscular volume (MCV)

Normal range: 80 to 100 femtoliters
This test measures the average volume of red blood cells, or the average amount of space each red blood cell fills. Irregularities could indicate anemia and/or chronic fatigue syndrome.

Mean corpuscular hemoglobin (MCH)

Normal range: 27 to 32 picograms
This test measures the average amount of hemoglobin in the typical red blood cell. Results that are too high could signal anemia, while those too low may indicate a nutritional deficiency.

Mean corpuscular hemoglobin concentration (MCHC)

Normal range: 28% to 36%
The MCHC test reports the average concentration of hemoglobin in a specific amount of red blood cells. Here again, we are looking for indications of anemia if the count is low, or possible nutritional deficiencies if it’s high.

Red cell distribution width (RDW or RCDW)

Normal range: 11% to 15%
With this test, we get an idea of the shape and size of red blood cells. In this case, “width” refers to a measurement of distribution, not the size of the cells. Liver disease, anemia, nutritional deficiencies, and a number of health conditions could cause high or low RDW results.

Platelet count

Normal range: 150,000 to 400,000 mL
Platelets are small portions of cells involved in blood clotting. Too many or too few platelets can affect clotting in different ways. The number of platelets may also indicate a health condition.

Mean Platelet Volume (MPV)

Normal range: 7.5 to 11.5 femtoliters
This test measures and calculates the average size of platelets. Higher MPVs mean the platelets are larger, which could put an individual at risk for a heart attack or stroke. Lower MPVs indicate smaller platelets, meaning the person is at risk for a bleeding disorder.

Additional Recommended Tests

While not part of the standard blood panel, I often order thyroid tests for my patients, especially if they report fatigue and weight gain, or weight loss and feelings of nervousness or hyperactivity. Some physicians dismiss borderline low or high tests, but I’ve found that these can be very helpful for identifying problems with the thyroid gland. Here are the ranges I look for in thyroid tests:

Test Normal Range

Thyroid-stimulating hormone (TSH) 0.3 to 3

Total T4 (total thyroxine) 4.5 to 12.5

Free T4 (free thyroxine) 0.7 to 2.0

Total T3 (total triiodothyronine) 80 to 220

Free T3 (free triiodothyronine) 2.3 to 4.2

If your test shows you are below the minimum numbers, you may be suffering from hypothyroidism, or low thyroid. If your scores are above the normal range, you may have an overly active thyroid, or hyperthyroidism. In either case, your physician can advise you on appropriate medication. You may also want to read my earlier newsletter on thyroid issues.

Vitamin D

Normal range: 30 to 74 ng/mL
Regular readers know I often recommend supplemental vitamin D, since deficiencies are very common. Too little vitamin D can put you at risk for broken bones, heart disease, cancer, and a host of other ailments. Our bodies can make vitamin D, but only when bare skin, free of sunblock and lotions, is exposed to sunlight. And even then, people of color and older individuals may not be able to manufacture sufficient quantities for optimal health. The best way to determine if you need supplements is to have a vitamin D test, known as 25-hydroxyvitamin D. Here again, doctors don’t always agree on how to interpret the results. My own preference is to see readings in the normal range.

There are quite a few more tests available, but the ones included here are among the most common.

To get accurate readings, be sure to follow your doctor’s instructions in preparing for tests. You may, for example, be asked not to eat and to drink only water for anywhere from a few hours to 12 hours beforehand. Please follow these instructions, or your results may be skewed, requiring additional tests or even unnecessary medications.

If you don’t understand something in your results, remember it’s okay to ask questions. Doctors are busy people, but you are entitled to the information. If your doctor can’t provide it, ask the nurse or physician’s assistant for help.

Knowing where you stand with these important parameters is essential for being proactive and owning your own health.

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