According to Gram Research analysis, changes made to a popular blood test for folate significantly affected how many people appeared to have low folate levels. A study of 178,323 blood tests in Italy found that when the test machine was updated, the proportion of people showing low folate jumped from 31% to 43%, even though actual folate levels didn’t change that much. This means test results can be affected by machine updates, not just by real changes in patients’ folate levels.
Researchers in Italy discovered that changes made to a popular blood test for folate (a B vitamin) significantly affected the results doctors were getting. By studying nearly 180,000 blood tests from 2022 to 2026, they found that when the test was updated, it started showing more people with low folate levels, even though the actual folate in their blood hadn’t really changed that much. This matters because doctors rely on these tests to decide if patients need folate supplements, so if the test isn’t accurate, patients might get unnecessary treatment or miss real problems.
Key Statistics
A study of 178,323 folate blood tests at San Raffaele Hospital in Milan found that updates to the Elecsys Folate III test machine increased the proportion of results below the deficiency cutoff from 31.2% in 2022-2023 to 42.9% in 2024-2026, a jump of more than 10 percentage points.
Research from 2026 showed that even after the test manufacturer made a correction in 2025, the high rate of low folate results persisted, suggesting the test changes affected how accurately it measured folate at the critical level where doctors diagnose deficiency.
A retrospective analysis of four and a half years of folate testing data revealed that test machine modifications were temporally associated with substantial changes in measured folate concentrations, indicating that assay-related bias may affect estimates of folate deficiency prevalence.
The Quick Take
- What they studied: How changes to a blood test machine (the Elecsys Folate III assay) affected folate test results and how many people appeared to have folate deficiency
- Who participated: 178,323 blood test results from patients at San Raffaele Hospital in Milan, Italy, collected between January 2022 and June 2026
- Key finding: When the test was updated, the number of people showing low folate jumped from about 31% to 43%, even though the actual folate levels didn’t change that much. This suggests the test itself, not real changes in patients, caused the difference.
- What it means for you: If you had a folate test done, the results might depend partly on when and where you got tested, not just your actual folate level. Talk to your doctor about what your specific results mean for your health.
The Research Details
Researchers looked back at nearly 180,000 folate blood tests done at one hospital in Italy over four and a half years. They tracked how the test results changed over time and compared them to when the test machine was updated. The test machine, made by a company called Roche, went through several changes during this time period, including updates to handle a substance called biotin better and corrections made by the manufacturer. By watching the patterns in the test results month by month, the researchers could see if the changes in results matched up with the changes to the test machine.
This type of study is called a retrospective analysis, which means the researchers looked at data that had already been collected for other reasons. They didn’t do a new experiment or follow patients over time. Instead, they used existing test results to figure out what happened. This approach is useful for spotting problems with lab tests because it uses real-world data from many patients.
The researchers looked at two main things: the average folate level each month and how many tests showed results below the cutoff level (5.38 ng/mL) that doctors use to say someone has low folate. By tracking these numbers over time and comparing them to when the test machine changed, they could see if the machine changes affected the results.
Lab tests are supposed to give accurate, consistent results so doctors can make good decisions about patient care. If a test machine changes and starts giving different results, doctors might think patients have problems they don’t actually have, or miss real problems. This study shows that even small changes to how a test works can have big effects on how many people are diagnosed with a deficiency. Understanding these changes helps doctors and hospitals know when they need to be extra careful about interpreting test results.
This study used a very large number of real test results from actual patients, which makes it strong. However, it only looked at one hospital in one city in Italy, so the results might not apply everywhere. The study couldn’t prove that the test changes definitely caused the differences in results, only that they happened at the same time. The researchers didn’t have information about whether patients’ actual folate levels changed or whether they were taking supplements, which could have affected the results. Because this is a real-world study rather than a controlled experiment, there could be other explanations for the changes they saw.
What the Results Show
The researchers found that folate test results changed dramatically over the four and a half year period, and these changes matched up with updates to the test machine. During 2022 and 2023, before major changes to the test, about 31% of patients showed low folate levels. But after the test was updated in 2024, this jumped to about 43%, an increase of more than 10 percentage points. This is a big change that happened relatively quickly.
Interestingly, when the manufacturer made a correction to the test in 2025, the average folate numbers went up a bit, but the number of people showing low folate stayed high at around 43%. This suggests that the test was measuring differently at the low end, where doctors decide if someone has a deficiency. The researchers found that the test changes seemed to affect low folate results more than high folate results.
The pattern was clear: stable results in 2022, an increase in 2023, a big drop after the 2024 update, and then a partial recovery in 2025. But even with the recovery, the number of people classified as having low folate remained much higher than before the changes. This tells researchers that the test machine itself was behaving differently, not that patients’ actual folate levels had changed so dramatically.
The study found that the test changes affected results in a way that was not consistent across all folate levels. The biggest problems appeared at the low end of the range, right around the cutoff point where doctors decide if someone has a deficiency. This is important because it means the test became less reliable exactly where it matters most for diagnosis. The researchers also noted that the biotin-tolerant version of the test, which was supposed to improve accuracy, was introduced along with other changes, making it hard to know which change caused which effect.
Previous research, mostly from countries where flour and other foods are fortified with folic acid, suggested that folate testing might not be very useful because deficiency is rare. However, this study was done in Italy, where foods are not routinely fortified with folic acid, so folate deficiency is more common. The findings suggest that conclusions from fortified countries might not apply everywhere. This study also adds to growing evidence that lab test machines need careful monitoring because small changes can have big effects on how many people are diagnosed with conditions.
This study only looked at one hospital in one city, so the results might not apply to other places or countries. The researchers couldn’t see individual patient information, so they couldn’t tell if the same people were tested multiple times or if different groups of patients were tested at different times. They also didn’t know if patients were taking folate supplements or if their diets changed, which could affect results. The study couldn’t prove that the test changes definitely caused the differences, only that they happened at the same time. Finally, the researchers didn’t have information about whether the test changes affected different types of patients differently.
The Bottom Line
If you’ve had a folate test, especially if it showed low levels, talk to your doctor about what it means for you specifically. Don’t assume a low result means you definitely have a problem without discussing it further. If you’re being treated for low folate, your doctor might want to repeat the test to make sure the treatment is working. Healthcare providers should be aware that folate test results can be affected by changes to the testing machine, not just by actual changes in patients’ folate levels. Confidence level: Moderate. This is based on one hospital’s data, but the findings are clear and important.
Doctors and hospitals who use folate tests should pay attention to this research. Patients who have had folate tests, especially those diagnosed with low folate, should know that test results can be affected by machine changes. People in countries without food fortification, where folate deficiency is more common, should be especially aware. This is less relevant for people in countries where foods are fortified with folic acid, where folate deficiency is very rare.
If you start taking folate supplements based on a test result, it typically takes several weeks to a few months to see improvements in symptoms like fatigue or weakness. However, the bigger issue here is making sure the test result is accurate in the first place. If your doctor recommends retesting, that usually happens 2 to 3 months after starting treatment.
Frequently Asked Questions
Can lab test machine changes affect my folate test results?
Yes. Research shows that updates to the Elecsys Folate III test machine caused the proportion of low folate results to jump from 31% to 43% between 2022 and 2026, even though patients’ actual folate levels didn’t change that much. This means your result might depend partly on when and where you were tested.
What does it mean if my folate test shows I’m deficient?
A low folate result suggests your body may not have enough of this B vitamin, which can cause fatigue and weakness. However, given recent test machine changes, discuss your specific result with your doctor to understand what it means for you and whether treatment is needed.
Should I get my folate test repeated if I was diagnosed with deficiency?
It’s worth discussing with your doctor, especially if you were tested in 2024 or later when the test machine was updated. Repeating the test at the same lab can help confirm whether you truly have low folate or if the result was affected by test machine changes.
Does this research apply to folate testing everywhere?
This study was done at one hospital in Italy, where foods aren’t fortified with folic acid. The findings may apply more to countries without food fortification, where folate deficiency is more common, than to countries where foods are fortified.
What foods can help if I have low folate?
Folate-rich foods include leafy greens like spinach and kale, legumes such as lentils and chickpeas, asparagus, broccoli, and fortified cereals. Eating these regularly can help maintain healthy folate levels alongside any treatment your doctor recommends.
Want to Apply This Research?
- If you’re tracking folate levels, record the date of your test, the result number, and which hospital or lab did the test. Note any symptoms like fatigue or weakness. This helps you and your doctor see patterns over time and notice if results seem unusual.
- Use the app to set reminders for folate-rich foods like leafy greens, legumes, and fortified cereals. Track your intake and any symptoms. If you’re taking a folate supplement, log when you take it and any changes you notice in energy or how you feel.
- If you have a folate deficiency diagnosis, use the app to track test dates and results over time. Compare results from the same lab when possible, since different labs might use different test machines. Note any changes in diet, supplements, or symptoms. Share this information with your doctor at follow-up visits to help them interpret your results accurately.
This article discusses research about folate blood testing and should not be used to diagnose or treat any medical condition. Folate test results should be interpreted by your healthcare provider in the context of your symptoms, diet, and medical history. If you have concerns about your folate levels or have been diagnosed with folate deficiency, consult with your doctor before starting any supplements or making dietary changes. The findings in this study apply specifically to one hospital in Italy and may not reflect testing practices everywhere. Lab test results can vary based on the testing method, laboratory, and timing, so discuss your specific results with your healthcare provider.
This research translation is published by Gram Research, the science division of Gram, an AI-powered nutrition tracking app.