A standard blood panel checks your cholesterol, your blood sugar, your triglycerides and a short list of liver enzymes. It does not check your bile acids. On 18 August 2026, researchers at the University of Toledo argued that this omission costs people the window in which liver trouble is still easiest to act on, and they published a way to close it.
None of this replaces the panel you already know. Our guide to reading liver function tests still covers the markers your doctor orders today. What the new work raises is the question that sits one step earlier: what if the liver sends up a flare before ALT and bilirubin notice anything at all?
What the 18 August study found
Bile acids are made by the liver to help digest fat. In normal conditions they shuttle between the liver and the intestine and stay largely out of the bloodstream. When liver cells struggle or bile flow is obstructed, they spill into the blood, a state called cholemia. Early on it is completely silent, which is exactly why it slips through.
The Toledo team, led by Matam Vijay-Kumar and Sadhana Kumari, expected high bile acids to make red blood cells more fragile. They found the opposite. Exposure to bile acids loads the red cell membrane with extra cholesterol whilst stripping out phospholipids, and the resulting membrane is stiffer, not weaker. Stiffer cells resist bursting when placed in a dilute solution, and that resistance can be measured.
The pattern held in several mouse models and, more importantly, in people. Blood from 23 patients with cholestatic liver disease at the University of Toledo Medical Centre behaved the same way as the mouse samples when compared against 23 matched controls without liver disease. The proposed test is deliberately unglamorous: about four extra microlitres of blood, taken at the same time as a glucose sample, dropped into solution, with an answer in ten to twenty minutes. A patent application has been filed.
Why this marker moves first
The argument for bile acids is not that they replace anything. It is that they are early. Conventional liver markers report damage that has already happened or bile flow that is already blocked, and they can stay inside their reference range while a slow process gathers pace.
| Marker | What it signals | On a routine panel? |
|---|---|---|
| ALT and AST | Liver cells leaking after injury | Yes, almost always |
| ALP and GGT | Bile flow already obstructed | Yes, usually |
| Bilirubin | Waste pigment the liver can no longer clear | Yes |
| Total bile acids | Bile spilling into blood, often before the above | No, ordered only on request |
That last row is the whole story. If you want to know what each of the other lines means on your own report, we cover ALT and what raises it, alkaline phosphatase, GGT and total bilirubin individually. Most of them travel together inside the wider comprehensive metabolic panel, which is where you will find them on your printout.
One place where bile acids are already standard
There is a clinical setting where this test is not experimental at all: pregnancy. In intrahepatic cholestasis of pregnancy, bile acids climb and the main symptom is relentless itching without a rash, often on the palms and soles and worse at night. Persistent night-time itching has many ordinary explanations, which our page on itchy feet at night works through, but in pregnancy it is the one symptom that should always prompt a bile acid measurement rather than a moisturiser.
The reason the threshold matters is stark. Guidance from the Society of Obstetric Medicine of Australia and New Zealand sets diagnosis at a non-fasting total serum bile acid of 19 micromoles per litre or above, calls 40 and above severe, and 100 and above very severe, the level associated with stillbirth. That is why Vijay-Kumar singled out pregnant women as the group with the most urgent need for a fast, repeatable test. Our overview of blood tests during pregnancy sets out what is routinely checked and what is not.
Latest scientific advances, translated
Searching PubMed and the Consensus database for the past three years turns up a consistent picture, and three findings are worth knowing if you are the one holding the report.
The first: bile acids really do move before the enzymes. A 2026 prospective cohort of 63 liver transplant recipients tracked bile acids daily after surgery and found they started rising 24 to 48 hours before liver enzymes did when the body began rejecting the graft. That is a very specific setting, but it is direct evidence of the sequence the Toledo team is banking on.
The second: bile acid panels can outperform ALT and AST at telling liver conditions apart. In 625 people with the full spectrum of hepatitis B related liver disease, a profile of individual bile acids separated healthy participants from patients with liver disease more accurately than conventional markers, and it also tracked response to antiviral treatment. Similar profiling in metabolic dysfunction-associated steatotic liver disease and in alcohol-related liver disease has pointed the same way. If you are following a fatty liver result, our article on the blood tests used to detect fatty liver covers what is currently available, and our piece on reading hepatitis test results handles the viral side.
The third, and the honest caveat: none of this is a diagnosis. In pregnancy research, combining two specific bile acids reached a diagnostic accuracy around 0.93 for cholestasis, which is genuinely good, and still short of a verdict. A raised bile acid level says the liver is under strain. It does not say why. Alcohol, medicines, a viral infection, a stone in the bile duct and metabolic fatty liver can all produce it, and separating them takes the rest of the workup.
What this changes for you today
Practically, nothing on your next form changes automatically. Bile acids are not on routine panels and this particular assay is patent-pending, not in clinics. But there are two situations where the test already exists and is worth asking about by name.
The first is pregnancy with itching that has no rash, especially on palms and soles at night. The second is a persistently abnormal or drifting liver result that nobody has explained, particularly if the pattern points to bile flow rather than cell injury. If your ALT keeps sitting above the line, our guide to the causes behind a raised ALT is the sensible first stop before adding new tests.
The broader point stands on its own. Your liver panel is a set of choices somebody made about which molecules are worth the cost of measuring, not a complete picture of your liver. Knowing what is missing from the page is part of reading it.
Frequently asked questions
Is a bile acid test available now?
The measurement itself is, in hospital and specialist laboratories, usually as a total serum bile acid on a fasting sample. What is new is the rapid whole-blood method described on 18 August, which is patent-pending and not yet in clinical use. If you need the number today, it is the conventional assay your doctor would order.
Would this show up on a normal check-up?
No. Bile acids are not part of a standard liver panel or a comprehensive metabolic panel anywhere in routine care. They are ordered deliberately, most often in pregnancy or when a cholestatic pattern needs explaining.
My liver enzymes are normal. Could my bile acids still be high?
It is possible, and that possibility is the entire premise of the research. Normal enzymes never fully exclude liver disease, because the liver has a large reserve and enzymes report injury rather than function. That said, in a person with no symptoms and no risk factors, normal enzymes remain reassuring.
What actually raises bile acids?
Anything that impairs liver function or obstructs bile flow. Cholestatic liver diseases, a blocked bile duct, drug-induced liver injury, cirrhosis and pregnancy-related cholestasis are the common routes. A single raised value is a prompt to look further, not an answer in itself.
Does itching always mean high bile acids?
No. Itching has many far more common causes, from dry skin to eczema to nerve irritation. What makes it worth investigating is the combination: itching without a rash, concentrated on palms and soles, worse at night, and above all during pregnancy.
Glossary
- Bile acids: compounds made by the liver from cholesterol that help digest fats and normally circulate between liver and intestine.
- Total serum bile acids: the laboratory test that measures all of them together in blood, usually reported in micromoles per litre.
- Cholemia: the presence of bile components in the bloodstream, typically because the liver or bile ducts are not clearing them.
- Cholestasis: reduced or blocked bile flow, whether inside the liver or in the ducts leading out of it.
- Intrahepatic cholestasis of pregnancy: a pregnancy-specific liver condition marked by itching and raised bile acids, needing obstetric monitoring.
- Osmotic resistance: how well a red blood cell withstands swelling in a dilute solution, the property this new screening method measures.
- Phospholipid: a fat molecule that forms cell membranes; losing it relative to cholesterol makes a membrane stiffer.
- Analyte: any substance a laboratory measures in a sample, such as glucose, bilirubin or bile acids.
Understand your own results
A liver panel only makes sense as a pattern. ALT and AST relative to each other, ALP and GGT read together, bilirubin split into its fractions, albumin and clotting alongside them, all against reference ranges that shift from one laboratory to the next. AI DiagMe reads your complete lab report and explains, line by line, what each result means in your situation, including which liver markers are actually on your page and how they fit together. Upload your report at aidiagme.com to get a clear reading before your next appointment.
Further reading
- The AST/ALT ratio: what it tells your doctor
- Full blood panel: every test it includes
- What belongs in a comprehensive blood panel
- HBs antigen: reading a hepatitis B result
- Gallbladder rupture: symptoms, causes and treatment
Sources
- University of Toledo. UToledo Researchers Develop Blood Test Targeting Overlooked Marker of Liver Disease. 18 August 2026. news.utoledo.edu
- News-Medical. UToledo researchers find new way to spot earliest warning signs of liver disease. 18 August 2026. news-medical.net
- Clinical Lab Products. Researchers Develop Rapid Blood Screening Method for Early Liver Disease Detection. 18 August 2026. clpmag.com
- Yeoh BS, Kumari S, Vijay-Kumar M, et al. Elevated circulating bile acids driven erythrocyte osmotic resistance marks hepatobiliary disease. American Journal of Physiology-Gastrointestinal and Liver Physiology. 2026. DOI
- Sundararajan VB, et al. Temporal profile of serum total bile acid levels and their value in the evaluation of early graft dysfunction in living donor liver transplantation. Clinical Transplantation and Research. 2026. Reference
- Mu J, et al. Serum Bile Acid Profiling Across the Full Spectrum of HBV-Related Liver Diseases in Chinese Population. Biomedicines. 2025. Reference
- Basuni A, et al. Exploring serum bile acids as potential noninvasive biomarkers for nonalcoholic fatty liver disease. Egyptian Liver Journal. 2024. Reference
- Hague W, et al. Intrahepatic cholestasis of pregnancy, diagnosis and management: a consensus statement of the Society of Obstetric Medicine of Australia and New Zealand. Australian and New Zealand Journal of Obstetrics and Gynaecology. 2023. Reference
- Gregorc P, et al. Evaluating the Effect of Bile Acid Levels on Maternal and Perinatal Outcomes in Intrahepatic Cholestasis of Pregnancy. Diagnostics. 2025. Reference
- Xu M, Xu K, Li J, et al. Expression Profiles and Diagnostic Value of Serum Bile Acids in Intrahepatic Cholestasis of Pregnancy. Annals of Clinical and Laboratory Science. 2025;55(1):72-78. Indexed in PubMed. PubMed
- Zhang G, Chen H, Ren W, Huang J. Efficacy of bile acid profiles in diagnosing and staging of alcoholic liver disease. Scandinavian Journal of Clinical and Laboratory Investigation. 2023;83(1):8-17. Indexed in PubMed. DOI
