Diagnosing Diabetes

People with diabetes are usually diagnosed in one of a few ways: For Type 1 diabetes, the diagnosis is typically based on symptoms (such as unquenchable thirst, constant urination, weight loss, and fatigue) followed by a blood glucose measurement. For Type 2 diabetes, it is generally based on the results of a fasting plasma glucose test or an oral glucose tolerance test that has been ordered because of risk factors for diabetes. (The HbA1c test is also being considered for use as a diagnostic tool.)


In cases where it’s not clear what type of diabetes a person has, there are other tests that can be done — primarily those that look for antibodies in the blood that would indicate an autoimmune condition. However, Type 1 and Type 2 diabetes are not the only types of diabetes: A few, less common, types exist, some of which are caused by particular genetic defects, and special tests may be necessary to diagnose those types.

Last week, the Chicago Tribune published an article about a nine-year-old girl, Lilly Jaffe, who was found to have a rare genetic mutation that caused her diabetes. In the three years since this discovery, 70 others nationwide were found to have the same mutation, which causes a form of diabetes (known as a monogenic diabetes, since it is caused by one gene) that can be treated with an oral drug rather than insulin despite the outward appearance of Type 1 diabetes. At the urging of the researchers who discovered Lilly’s condition, the state of Illinois passed a law last month requiring doctors to register all children who develop diabetes before they are 12 months old in a database. (This type of diabetes almost always occurs within the first six months of life.) The researchers hope that by analyzing the database, likely cases of Lilly’s type of monogenic diabetes can be detected and then followed up. This condition is assumed to be severely underdetected, with potentially 2,000 cases in the United States.

But Lilly’s is not the only type of diabetes believed to be frequently underdetected or misdiagnosed. Maturity-Onset Diabetes of the Young (MODY), another type of monogenic diabetes that tends to begin in young adulthood and can usually be treated without insulin, is often misdiagnosed as Type 1 diabetes; the genetic test to detect MODY is often not performed. Similarly, Latent Autoimmune Diabetes in Adults (LADA) is often misdiagnosed as Type 2 diabetes, and oral drugs are prescribed when insulin is needed. This confusion could be averted in many cases by testing for certain antibodies associated with Type 1 diabetes.

Do you support the idea of a mandatory registry for certain cases of diabetes? Given that less common forms of diabetes are often misdiagnosed as Type 1 or Type 2 — and that still-unknown varieties of diabetes may exist — should more tests be required at diagnosis for everyone? Have you received, or do you suspect you may have received, a wrong diabetes diagnosis? If you had good blood glucose control despite an inaccurate diagnosis, would it matter to you that your diabetes was known by the wrong name? What if you were taking insulin and might be able to take an oral drug instead? Leave a comment below!

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  • jhrbr

    Please stop perpetuating the negative image of insulin. For most of us it is a better medication because it has virtually no side effects, especially when compared to the oral medications prescribed for the treatment of type 2 diabetes.

    I’ve been down both path’s of treatment, insulin with my second pregnancy, then oral meds for ten years when I was diagnosed type 2, now insulin again with the correct diagnosis of LADA. I begged the doctor that was treating me as a type 2 for two years to put me on insulin. She refused, I knew it was a better medicine for me because I had been on it before.

    The medical field is getting it wrong and scaring people away from one of the best treatments available because it is considered “bad” to be on insulin.

  • Sally Smart

    I think it is important to find out what type we all have. I would rather it be named for sure and then we have a chance. I was missdiagnosed for a few years when a doctor who did not seem to know what I had thought it was heart problems and then allergies, I got a new doctor who said it was galbladder problems and it has to come out. Because of my discription of the pain my old doctor was confused and it took a lot of serious pain meds and pain before I found out even tho my mom said it was my galbladder, It was even thought to be anxiety and I was on medicine for that. A miss diagnosis is a serious peoblem and if more types are showing up or being realized we need to know. I would take extra testing if I thought it was not type 2 or was a different side of type 2 even.

  • lassengrl

    I think we should know the real diagnosis. My daughter is 21 with a mental disability and was told a year ago she has type 2. She had lost 40 lbs, was tired and thirsty. They put her on oral meds. Her period stopped after she started medication and has not come back. I feel we don’t have the whole story.Perhaps she is on the wrong meds.

  • Paula

    I support a database and further testing to determine what form of diabetes a person has. My daughter was diagnosed at age 3 with Type 1. She is on an insulin pump and is now 14 and a normal teenager. If a young child could use oral meds instead of insulin, I think that would be much better. Syringes, insulin, fingerpricks, highs, and lows all rob young children of their childhood. My daughter had to grow up with it, and until there’s a cure, anything that eliminates needles and insulin would be a great thing!

  • Timothy Miller

    I agree with the first comment posted today. About insulin and pills for type 2 diabetes. Facts that insulin does not have the bad side effects of oral meds for diabetes. I think by reading new studies on it, that they are finding ou8t to that people with type two diabetes are better off on insulin. I controlled my type two by diet losing weight and exercise. However I have kidney damage now, that I think came from pills. Read some of the print outs from your pharmacy on the drugs you take with diabetes. Is enough to scare you half to death. May or will cause kidney damage. Is not something I want to take for years. And I did. Now in trouble. Respectfully Submitted T.M. Florida

  • Robert Schauer

    I was diagnosed with Type 2 about 9 years ago. I was then about 59 years old. I had a history of this type in my family. My grandmother, mother, older brother, and younger sister have all been diagnosed with this dease. I am currantly taking insulin therapy plus I take Glucafage twice daily. My family has a history of being overweight. My diagnosis was missed for five years, by the doctor I had at the time. First symptom was loosing feeling in my feet. He didn’t equate that with the raised blood glucose in my physicals and so it wasn’t caught until I started having the other symptoms. When I was tested in the emergency room my blood glucose was at 485. The doctor that took me as a patient after that thought I might have a different type of diabetes that type 2. Hope this will be helpful to someone else who is misdiagnosed. Bob

  • David F. Babb

    I was diagnosed with diabetes 5 years ago at age 54. My father died at the age of 53 from complications associated with type 1.
    My symptoms came on suddenly and dramatically. Extreme thirst, frequent urination, fatigue and weight loss.
    I am 5′ 8″ tall and never weighed more than 150 lbs. I was an active runner and cyclist for many years.
    My doctor diagnosed me as type 2 after nothing more than a single glucose check in his office.
    He put me on metformin which helped a little, but not for long. Within 8 months I was on the maximum dosage…still tired and my weight was down to 128 lbs.
    He finally ordered an antibody and c-peptide test.
    I am LADA.
    I was immediately started on insulin. I felt like a man dying of thirst in the desert who had been given a cold glass of water. I began to gain the weight back and soon felt much better.
    Yes, I feel strongly that doctors are too quick to assume type 2 without administering the proper tests.

  • Douglas T. Hawes

    Perhaps the diagnosis of Diabetics should automaticly be followed by a referral to a specialist or a hospital that can make further diagnoses. I had not realized how many types of Diabetes there were out there. We have come a long way since my father was diagnosed as Diabetic in the early 30s. Only a specialist is apt to have the training to make a correct diagnosis.

  • M. Yarrington

    I agree that a person who is diabetic should get the proper tests needed to determine which type it is. In my case, I was 74 years old when I started to lose weight and was extremely thirsty. My family practitioner suggested I have an A1C test and the result was a high of 13.10. I had had a physical the prior June and at that time my fasting sugar was in the 90’s. However, because of my age it was assumed that I had Type 2 diabetes and different medications were tried. After about a year of this and without much success in controlling my sugar numbers, I decided to go to an endocrinolgist. When he heard my story including the sudden onset, he immediately suggested that I had Type 1. As he said with a twinkly in his eye, “You are 74 years old and you have Juvenile Diabetes.” He immediately put me on insulin and prescribed further tests to confirm that his decision was right. I have now been on insulin for 3 years and have much better control of my sugar numbers.

  • David J.

    In 1989 at the age of 24 with a sugar of over 300 I was started with insulin in the doc. office. In 2000 I was tested to qualify for an insulin pump. The test showed I was Type I. When I changed to a closer endocrinologist in 2006 the test said I was Type II. One side effect of insulin I have a problem with is the weight gain. Yet that is still better than any oral drugs and their side effects.

  • Becky

    I do not know what type of diabetes I have. Over 12 years ago a high random glucose test led to an A1c test which was 7. However, my fasting glucose tests always came back “normal” so I was not diagnosed with diabetes. Five years ago, with a different doctor, I was diagnosed as type 2. However, I am atypical, the usual treatments did not work and I am now on insulin. The medical profession seems to think the cause and type are not important as long as the current treatment works. If more testing had been done initially, I would have been diagnosed sooner. I also wonder about my children and what their chances of developing it are. I think more testing is important. I think the fasting glucose test is inadequate. I would like to know what type of diabetes I have.

  • jan

    I was diagnosed type 2 for 7 years.My HBa1c is 9 My readings range from 8 to 10 in the morning 7 to 9 before lunch 9 to 11 before tea.i have been having a problem with my eyes going blurred.
    No one seems to even look at my book with the readings im taking metformin 2-500mg tabs twice a day.zestril 5 mg and simvastatin 40 mg.i think my biggest problem is i have 2 doctors one in England and one in Saudi Arabia[as my husband works between the two places] and neither doctor seem botherd with my treatment i feel im the one pushing for answers.Iv given up.
    I am so glad i found you on internet and that other people are having problems and that i find some answers. thank you

  • sam jacob

    Don’t lose hope. Don’t be negative. It’s better to ask directly your doctor for what’s best for the patient, right?

  • E. Elson

    I have been struggling with the management of my blood sugar for many years. I have been prescribed oral hypoglycemeic agents when what I really needed was minute doses of insulin. Eventually my pancreas stopped producing insulin and I was maintained on an insulin pump for awhile. Then I started having frequent lows at a very low basal rate. My provider would not consider that I had started to make insulin again. Eventually I stopped the basal rate and administered small boluses with each meal.

    To make a long story short, I am now off insulin but my insulin production has decreased considerably in a year. What’s a girl to do?