LADA (latent autoimmune diabetes in adults) is more common than most people realize. Estimates suggest that 4% to 14% of everyone currently diagnosed with type 2 diabetes may actually have LADA instead. That makes it one of the most frequently misdiagnosed forms of diabetes, hiding in plain sight among the much larger type 2 population.
How Common LADA Actually Is
LADA sits in an unusual spot. It’s far less common than type 2 diabetes, which accounts for roughly 90% of all diabetes cases worldwide. But because type 2 is so prevalent, even a small percentage of misdiagnosed cases within that group translates to a large number of people. If 4% to 14% of type 2 diagnoses are actually LADA, that potentially means millions of people globally are living with the wrong diagnosis.
LADA is also more common than classic type 1 diabetes in adults. Some researchers consider it the most common form of autoimmune diabetes overall, simply because so many cases go unrecognized. The problem is that most adults who develop diabetes are assumed to have type 2 based on their age alone, and the antibody testing that would reveal LADA isn’t part of routine screening.
Why LADA Gets Missed So Often
The core issue is that LADA looks like type 2 diabetes at first. It typically appears after age 30, blood sugar is elevated, and the person may even be overweight. Standard treatment with lifestyle changes and oral medications can work for a while, which reinforces the type 2 diagnosis. There’s no obvious reason for a doctor to dig deeper unless the patient stops responding to treatment sooner than expected.
What separates LADA is what’s happening underneath. The immune system is slowly attacking the insulin-producing cells in the pancreas, the same process that drives type 1 diabetes. But in LADA, this destruction unfolds over months or years rather than weeks. That gradual timeline is what creates the confusion. A person with LADA can manage their blood sugar with pills for a year or two, sometimes longer, before the damage progresses enough that insulin becomes necessary.
The only reliable way to confirm LADA is through blood tests that most doctors don’t routinely order. One checks for specific immune proteins called GAD antibodies, which signal autoimmune activity against insulin-producing cells. The other measures C-peptide, a marker of how much insulin the body is still making on its own. A person with LADA will test positive for autoantibodies while still producing some insulin early on. Without these tests, the diagnosis stays hidden.
How LADA Differs From Type 1 and Type 2
LADA shares genetics with both type 1 and type 2 diabetes, which is part of why it’s been called “type 1.5” informally. People with LADA carry some of the same high-risk immune system genes found in type 1 diabetes, and these genes appear significantly more often in LADA than in type 2. But LADA patients carry fewer of these risk genes than people diagnosed with type 1 before age 30. About 30% of people with LADA have none of the classic high-risk gene variants at all, compared to only 12% of the broader type 1 population.
Interestingly, when researchers compared LADA to type 1 diabetes diagnosed after age 30, the genetic profiles looked nearly identical. This has led some scientists to argue that LADA isn’t really a separate disease but rather a slow-developing form of type 1 that happens to start later in life. The debate isn’t settled. The Immunology of Diabetes Society defines LADA by three criteria: onset after age 30, no need for insulin during the first six months after diagnosis, and the presence of circulating autoantibodies. But even experts acknowledge there’s no universally agreed-upon diagnostic standard.
What Happens After Diagnosis
The defining feature of LADA is progression. Unlike type 2 diabetes, where the body still produces insulin but can’t use it efficiently, LADA involves a steady loss of insulin-producing capacity. Most people with LADA will eventually need insulin injections. The timeline varies widely. Some people transition within months, while others manage for several years on oral medications before their pancreas can no longer keep up.
Certain markers help predict how quickly this transition will happen. Research from a large Japanese study found that people with higher levels of GAD antibodies, younger age at onset (under 47), and lower fasting C-peptide levels were more likely to progress to insulin dependence sooner. If your antibody levels are relatively low and your C-peptide is still healthy, you may have a longer window before insulin becomes necessary.
Getting the correct diagnosis matters because treatment strategies differ. Some type 2 medications that push the pancreas to produce more insulin can actually accelerate the destruction of the remaining insulin-producing cells in someone with LADA. Early identification allows for a treatment plan that preserves whatever insulin production is left, potentially slowing the progression and making blood sugar easier to manage over the long term.
Who Should Consider Testing
Certain patterns should raise suspicion for LADA. You’re diagnosed with type 2 diabetes but you’re not significantly overweight. Your blood sugar becomes harder to control despite following your treatment plan. You needed to escalate medications faster than your doctor expected. You have a personal or family history of other autoimmune conditions like thyroid disease, celiac disease, or rheumatoid arthritis.
None of these individually confirm LADA, but together they paint a picture worth investigating. A GAD antibody test is a simple blood draw, and it can save years of ineffective treatment. If you were diagnosed with type 2 in your 30s, 40s, or 50s and your medications seem to be losing effectiveness, asking about antibody testing is reasonable. Given that up to one in seven people with a type 2 diagnosis may actually have LADA, it’s far from a long-shot possibility.