- 01Low albumin measures illness
Low albumin measures illness, not diet, and ASPEN advises against using it to judge nutrition 3. The useful question is which illness is lowering it, and a CRP, liver tests and a urine protein test answer it.
Albumin is the most plentiful protein in your blood. The liver makes it, about 10 to 15 grams a day, and it holds water inside your blood vessels and carries calcium, zinc, hormones and many medicines around the body 1. A low albumin, called hypoalbuminemia, happens in four ways: the liver makes less; inflammation switches production down and lets albumin seep out of the vessels; the kidneys, gut or skin lose it; or extra fluid dilutes it. Because albumin is the largest share of the protein in blood, total protein usually drops with it.
Free, no accountRead your blood testGot a liver or metabolic panel with a low albumin? Paste it in to see where your albumin, total protein and globulin sit, line by line.Read my results
For the normal range and what albumin does day to day, see the parent page on albumin. This page covers the low side only. A high albumin has its own page.
How low is low albumin?
Where an example albumin of 3.1 g/dL fallsg/dL
| Albumin (g/dL) | Albumin (g/L) | What it usually means | How soon to act |
|---|---|---|---|
| 3.5 to 5.0 | 35 to 50 | Typical adult range | Nothing to do |
| 3.0 to 3.4 | 30 to 34 | Mildly low. Common after a cold, an infection or surgery, in pregnancy and in older age | Usually a recheck in 4 to 8 weeks with your doctor, if you feel well and the reason is clear |
| 2.5 to 2.9 | 25 to 29 | Moderately low. Usually an ongoing illness or a liver, kidney or gut cause | See a doctor within a couple of weeks for urine and liver tests |
| 2.0 to 2.4 | 20 to 24 | Markedly low. Ankle and leg swelling becomes more likely | See a doctor within the week |
| Under 2.0 | Under 20 | Severely low. Fluid in the legs, belly or around the lungs is common | See a doctor within days even without symptoms; same day if you are swollen or breathless |
Two things change how to read the number. First, labs use different methods to measure albumin, and some read a little higher than others, especially at low levels, so a 3.3 at one lab and a 3.0 at another can be the same blood. Compare results from the same lab. Second, one result is a snapshot; a falling albumin across two or three draws means more.
What causes low albumin (hypoalbuminemia)
Albumin is a negative acute-phase protein, which means the liver makes less of it whenever the body is fighting something. The signalling molecules of inflammation, such as interleukin-6 and TNF-alpha, turn albumin production down within days 2. At the same time, inflamed blood vessels leak, and albumin moves out of the blood into the tissues. That is why illness is the commonest cause of low albumin in hospitals and GP clinics. For how CRP and the other inflammation tests work, see inflammation markers explained.
Acute-phase proteins have been defined as those whose plasma concentrations increase or decrease by at least 25 percent during inflammatory disorders.Gabay C, Kushner I, New England Journal of Medicine, 1999 2
Common causes
- Inflammation and recent illness: a chest infection, flu, COVID-19, a flare of arthritis or inflammatory bowel disease, or recovery from surgery. A high CRP or hs-CRP beside a low albumin points this way 2.
- Liver disease. A scarred liver (cirrhosis) makes less albumin, and doctors use albumin to grade how advanced cirrhosis is. Long-standing fatty liver that has progressed to scarring can do the same.
- Dilution: large volumes of intravenous fluid in hospital, heart failure that holds extra water, and pregnancy, where blood plasma volume expands.
- Older age: albumin drifts down a little with age, and older adults more often carry a chronic illness that lowers it.
Less common causes
- Kidney loss. Damaged kidney filters let albumin pass into the urine. Small leaks are common in diabetes and chronic kidney disease but rarely lower blood albumin much; heavy leaks do.
- Gut loss: protein-losing enteropathy, where protein leaks through the bowel wall, seen in Crohn's disease, coeliac disease and some lymph vessel disorders.
- Skin loss after large burns or widespread skin disease.
- True protein-energy malnutrition: eating disorders, heavy alcohol use, malabsorption, or a frail older person eating very little for weeks. In someone otherwise well, this is uncommon 3.
Must-not-miss causes
- Nephrotic syndrome: heavy protein loss in the urine (more than 3.5 g a day in adults) with albumin under 3.0 g/dL and swelling 5. Signs are new puffiness around the eyes, swollen legs and foamy urine. It raises the risk of blood clots, so calf pain or breathlessness with these signs needs care the same day.
- Decompensated cirrhosis: low albumin with a swelling belly, yellow eyes or skin, confusion or vomiting blood.
- Severe infection or sepsis: low albumin with fever, a racing heart, confusion or low blood pressure.
- Myeloma and other plasma cell disorders: a low albumin with a high globulin, bone pain, anemia or a high calcium. A doctor checks this with a protein electrophoresis test (a blood test that separates the proteins to look for an abnormal antibody).
In the same analysis, each 1 g/dL fall also raised the odds of complications by 89% 4. The number measures how sick the person is. If you are well and your albumin is 3.0 to 3.4 after a cold, it does not apply to you. Albumin infusions are kept for specific hospital situations, and they do not remove the cause of the low level, which is why doctors treat the cause.
Is low albumin caused by not eating enough protein?
Rarely, in someone who is otherwise well. Healthy people on a low-protein diet usually keep a normal albumin until starvation is severe and prolonged, because the liver protects its output and albumin lasts a long time in the blood. The American Society for Parenteral and Enteral Nutrition (ASPEN) advises against using albumin or prealbumin to judge nutrition, because both mainly reflect inflammation and how ill someone is 3. A low albumin after flu reflects the flu and recovers as the flu clears.
Intake does matter in a smaller group: older adults eating little, people with an eating disorder, heavy alcohol use, or a gut disease that blocks absorption. In those people, a dietitian works out protein and calorie needs. The general adult reference intake is 0.8 g of protein per kilogram of body weight a day. The calculator below gives your own daily grams.
CalculatorProtein calculatorYour daily protein grams from your weight, age and activity, for when diet is part of the picture.Work it out Low total protein and low albumin together
Total protein is albumin plus globulins, the second family of blood proteins, which includes antibodies. On a low total protein blood test, the normal range is usually about 6.0 to 8.3 g/dL; a total protein below your lab's lower limit, usually about 6.0 to 6.4 g/dL, is low. Globulin is total protein minus albumin, and the albumin/globulin (A/G) ratio is albumin divided by globulin. When total protein is low, the pattern of all three tells you more than any one line.
| Albumin | Globulin | Total protein | What the pattern leans toward |
|---|---|---|---|
| Low | Normal | Low | Albumin made less or lost on its own: inflammation, early liver disease, kidney leak |
| Low | Low | Low | Whole-protein loss or dilution: gut loss, burns, severe malnutrition, IV fluids, pregnancy |
| Low | High | Normal | Masking: high globulins hide the low albumin. Chronic inflammation, chronic infection, cirrhosis, or a plasma cell disorder such as myeloma. The A/G ratio is low |
| Normal | Low | Low | Few antibodies (immunoglobulins); a doctor may check IgG, IgA and IgM |
The masking row is the one a total protein line alone misses. A total protein of 7.0 g/dL looks fine, but with an albumin of 3.0 g/dL the globulin is 4.0 g/dL and the A/G ratio is 0.75. That combination is worth a doctor's look, and the A/G ratio page explains what moves it.
The protein lines that sit with albumin
Symptoms of low albumin
A mildly low albumin, 3.0 to 3.4 g/dL, usually causes no symptoms. Albumin supplies most of the pull that keeps water inside blood vessels, so as it falls further, fluid seeps into the tissues. As a rough guide, swelling becomes likely below about 2.5 g/dL and common below 2.0 g/dL: puffy ankles and legs that dent when pressed, a puffy face and eyelids in the morning, fluid in the belly (ascites) or around the lungs.
Other symptoms usually belong to the cause rather than to the albumin:
- Foamy urine points to the kidneys.
- Yellow eyes and easy bruising point to the liver.
- Diarrhea and weight loss point to the gut.
- Tiredness is common and comes from the underlying illness.
Which cause is it? The tests that sort it out
Doctors usually work through the causes in order of how common they are: inflammation first, then the liver, then the kidneys, then the gut, with the heart and dilution checked when the story fits. The table maps what you may already see on your report to the likely cause and the usual next test.
| If low albumin comes with | It leans toward | Usual next test |
|---|---|---|
| High CRP or hs-CRP, a recent infection or operation | Inflammation, the commonest cause | Repeat albumin after recovery |
| Raised ALT or AST, high bilirubin, low platelets, a long INR (blood that takes longer to clot) | The liver not making enough | Full liver panel, INR, liver ultrasound |
| Protein or albumin in the urine, foamy urine, puffy eyes | Kidney loss | Urine albumin/creatinine ratio or protein/creatinine ratio, creatinine and eGFR (kidney filtering rate) |
| Diarrhea or weight loss with clean liver and urine tests | Gut loss or poor absorption | Stool alpha-1 antitrypsin (a stool test that shows protein leaking from the gut), coeliac antibodies |
| Breathlessness and swollen legs | Heart failure with fluid overload | A BNP or NT-proBNP blood test (a hormone the heart releases under strain), and a heart scan |
| Pregnancy or recent IV fluids | Dilution | Usually none beyond a later recheck |
For background on the liver and kidney lines in this table, see liver enzymes explained and kidney function explained.
Other results a low albumin changes
Albumin carries several things that labs measure, so a low albumin makes some other results look lower than they are.
- Calcium. Much of the calcium in blood rides on albumin, so total calcium reads falsely low. The usual correction is corrected calcium = measured calcium + 0.8 × (4.0 minus albumin in g/dL), shown on the corrected calcium line. A calcium of 8.4 mg/dL with an albumin of 3.0 corrects to 9.2, which is normal. When albumin is very low, an ionized calcium test is more accurate than the formula.
- Zinc. Most zinc in blood is bound to albumin, so serum zinc reads lower when albumin is low, and a low zinc result may not mean a zinc deficiency. If zinc still looks low once albumin is accounted for, see zinc deficiency.
- Medicines. Drugs that bind tightly to albumin, such as phenytoin and warfarin, have more free, active drug when albumin is low. Doctors may check a free phenytoin level or the INR more often.
- Anion gap. Albumin carries much of the unmeasured negative charge, so a low albumin shrinks the anion gap and can hide a high one. Doctors adjust the anion gap for albumin when they read it.
CalculatorCorrected calcium calculatorCalcium adjusted for your albumin, so a low calcium line does not send you down the wrong path.Work it out Low albumin in pregnancy, older age and after illness or surgery
Albumin falls through pregnancy because plasma volume expands. Typical reference values are about 3.1 to 5.1 g/dL in the first trimester, 2.6 to 4.5 g/dL in the second and 2.3 to 4.2 g/dL in the third 6, so a third-trimester albumin of 2.8 g/dL is expected. Swelling with high blood pressure, headache or protein in the urine in later pregnancy is different: that can be pre-eclampsia and needs the maternity team the same day.
Older adults often run slightly lower albumin. Posture changes the draw too: albumin reads higher when blood is drawn sitting than lying down, and a long tourniquet time raises it further.
After an infection or an operation, albumin often drops within days and climbs back slowly, because albumin lasts about three weeks in the blood and the liver has to rebuild the pool 1. A recheck too soon can look like no progress.
How to raise low albumin
Albumin rises when its cause is treated. The table shows what that means for each cause.
| Cause | What raises albumin |
|---|---|
| Inflammation or infection | The illness settling; albumin follows over the next few weeks |
| Liver disease | Removing the cause, such as alcohol, fatty liver or viral hepatitis. The evidence on supplements for liver health is summarised separately; none of them raise albumin directly |
| Kidney protein leak | Treatment of the kidney disease, often with a medicine a doctor prescribes to lower the leak, such as an ACE inhibitor or an ARB 5 |
| Gut loss or poor absorption | Treatment of the gut disease by a gastroenterologist |
| Low intake | More protein and calories, planned with a dietitian |
Eggs, meat, beans and protein powder raise albumin only when low intake is the cause, which is the minority described above. Albumin infusions through a drip are used in hospital for specific situations, such as draining large amounts of fluid from the belly in cirrhosis; they are not used to correct a low lab number, because the cause remains. Recheck 4 to 8 weeks after the cause is treated, at the same lab, to see the trend.
When to see a doctor about low albumin, and how fast
A routine follow-up is enough for an albumin of 3.0 to 3.4 g/dL found once, with a clear recent reason such as an infection or surgery, in someone who feels well: recheck in 4 to 8 weeks. If it is still low on the second draw with no obvious reason, a doctor will usually order a CRP, a liver panel and a urine protein test as the first round of the work-up. At your appointment you can say: "My albumin was 3.2. Could we check CRP, a liver panel and a urine albumin/creatinine ratio, and repeat albumin in 6 weeks?"
Citations
- Gounden V, Vashisht R, Jialal I. Hypoalbuminemia. StatPearls, NCBI Bookshelf, updated 2024
- Gabay C, Kushner I. Acute-phase proteins and other systemic responses to inflammation. N Engl J Med. 1999;340:448-454
- Evans DC et al. The use of visceral proteins as nutrition markers: an ASPEN position paper. Nutr Clin Pract. 2021;36:22-28
- Vincent JL et al. Hypoalbuminemia in acute illness: is there a rationale for intervention? A meta-analysis of cohort studies and controlled trials. Ann Surg. 2003;237:319-334
- KDIGO 2021 Clinical Practice Guideline for the Management of Glomerular Diseases. Kidney Int. 2021;100(4S):S1-S276
- Abbassi-Ghanavati M, Greer LG, Cunningham FG. Pregnancy and laboratory studies: a reference table for clinicians. Obstet Gynecol. 2009;114:1326-1331
Educational context only, not medical advice or a diagnosis. Always discuss your results with a clinician.
