Albumin
Albumin is the main protein in blood. Two US survey laboratory manuals print adult ranges of 3.5 to 5.0 and 3.7 to 4.7 g/dL. Lower values go with more deaths and heart disease, yet trials that raised albumin by infusion in sepsis and cirrhosis found no benefit. A nutrition society states that it reflects inflammation, not nutrition status.
- Status
- Part of routine comprehensive metabolic and liver blood panels, ordered by a clinician and also sold direct to consumers by some US laboratories. FDA classifies albumin test systems, which measure albumin in serum and plasma, as class II devices [1]. This page covers albumin in blood, not albumin in urine.
- Measures
- The concentration of albumin in serum or plasma. Albumin makes up about 60% of total serum protein, carries fatty acids, bilirubin and hormones, and maintains the osmotic pressure of serum [2].
- Also called
- albumin, serum albumin, albumin serum, plasma albumin, ALB, albumin blood test
- Tested for
- liver function, kidney disease, nutrition status, protein intake, swelling, inflammation, surgical risk
Strong several reviews agree · Moderate one review or consistent trials · Limited one or a few small studies · Untested no study in people, listed with what it rests on
Linked in research3
- ModerateLinked to more deaths at lower albumin, with the odds of death 24% to 56% higher for each 0.25 g/dL lower in a review of cohort studies.
- ModerateLinked to more cardiovascular disease at lower albumin, about 85% more for each 1 g/dL lower in a meta-analysis of 14 studies.
- LimitedOne US veterans cohort linked lower albumin before surgery to more deaths within 30 days, from under 1% above 4.6 g/dL to 29% below 2.1 g/dL.
Reported risks0
No risks sourced yet.
Reference ranges
Each range is the one its source published, in g/dL. Also reported in g/L. Where sources differ, each is shown.
US national survey laboratory procedure manual, 2017 to 2018
Adults, as the reference range printed for the assay · [2], [3]
| Range | What the source calls it |
|---|---|
| below 3.5 g/dL | No name given |
| 3.5 to 5 g/dL | "reference range" |
| above 5 g/dL | No name given |
The reference range listed in the laboratory manual for the method used in the 2017 to 2018 US National Health and Nutrition Examination Survey (Roche Cobas 6000, bromcresol purple dye). It is the range attached to that assay, not one derived from survey participants [2]. The survey's data file reports each result in both units, and its lowest and highest values, 2.1 and 5.4 g/dL, appear as 21 and 54 g/L [3].
US national survey laboratory procedure manual, 2015 to 2016
Adults older than 18, as the reference range printed for the assay · [4]
| Range | What the source calls it |
|---|---|
| below 3.7 g/dL | No name given |
| 3.7 to 4.7 g/dL | "reference range" |
| above 4.7 g/dL | No name given |
From the manual for the method used in the 2015 to 2016 survey (Beckman UniCel DxC 800, bromcresol purple dye, run by Collaborative Laboratory Services). The manual states that its reference ranges were established from wellness participants with an age mix similar to the laboratory's patients. Its table heads the range column mg/dL, while the manual labels the survey variable g/dL and gives its early-report threshold as less than 2.0 g/dL, so this block reads the range as g/dL. Two assays that both use the same dye, in the same national survey, print different ranges [4][2].
US national survey laboratory procedure manual, 2015 to 2016, children aged 1 to 18
Children and adolescents aged 1 to 18 · [4]
| Range | What the source calls it |
|---|---|
| below 3.1 g/dL | No name given |
| 3.1 to 4.8 g/dL | "reference range" |
| above 4.8 g/dL | No name given |
The manual attributes its pediatric ranges to a 1995 multicenter guideline for the analyzer, built on data from Montreal, Miami and Denver. It prints one range for the whole span from 1 to 18 [4].
US national survey laboratory procedure manual, 2015 to 2016, infants under 1 year
Infants from birth to 1 year · [4]
| Range | What the source calls it |
|---|---|
| below 2.7 g/dL | No name given |
| 2.7 to 4.8 g/dL | "reference range" |
| above 4.8 g/dL | No name given |
From the same manual and the same 1995 pediatric guideline for the analyzer [4].
Šupak-Smolčić and colleagues, Croatian pregnancy cohort, 2025, first trimester
Pregnant women at 11 to 14 weeks of gestation · [5], [6]
| Range | What the source calls it |
|---|---|
| below 3.81 g/dL | No name given |
| 3.81 to 4.62 g/dL | "reference interval" |
| above 4.62 g/dL | No name given |
The central 95% of results in 299 women with singleton pregnancies at one Croatian center, measured with bromcresol green dye on a Roche Cobas 6000. The paper prints the interval as 38.1 to 46.2 g/L, written here in g/dL. The authors compare it with the 40.6 to 51.4 g/L range that Croatian laboratories use for non-pregnant women and judge albumin to be lower in early pregnancy by a clinically relevant amount. The study covers the first trimester only [5]. A study of 103 pregnant women and 103 matched controls found albumin significantly lower in all three trimesters and attributed it to hemodilution, without giving limits in its abstract [6].
What has been shown to move it
Shown to lower it1
Small drops in blood counts and albumin
Small drops in hematocrit, hemoglobin, white cells and albumin were seen on terazosin in trials, which the label attributes to blood dilution. PSA did not change.
The numbers and sources
- How common
- How often is not known: the sources give no rate.
- Effect
- Small but statistically significant decreases in hematocrit, hemoglobin, white blood cells, total protein and albumin were seen in controlled trials. Treatment for up to 24 months had no significant effect on PSA [19].
- Population
- People in terazosin controlled trials [19].
- Sources
- [19]
- Caveats
- The label gives no size for the drops.
Tested, and not shown to change it2
Nutritional status
Nutritional measures such as albumin and lean mass did not differ from a low-protein diet alone in adults with chronic kidney disease.
The numbers and sources
- How common
- How often is not known: the sources give no rate.
- Effect
- Albumin, mid-arm muscle circumference, lean body mass and subjective global assessment did not differ from a low-protein diet alone [1]. Albumin and cholesterol did not fall against placebo [3]. In the 15-month trial, nutritional measures did not change and no adverse reactions occurred [5]. Across protein restriction trials, 12 studies reported no protein energy wasting and 3 reported small numbers in each group [6].
- Population
- Adults with CKD [1][3][5][6].
- Sources
- [1], [3], [5], [6]
- Caveats
- The 15-month trial enrolled well-nourished patients who had followed the diet in a run-in phase [5]. Few studies reported weight [6].
Lower testosterone at 6 g a day
One small trial found 6 g a day for 14 days lowered total and free testosterone in 24 trained men. A 12-week trial found no change.
Estradiol, SHBG and albumin did not change.
The numbers and sources
- How common
- How often is not known: the sources give no rate.
- Effect
- In trained men, 6 g a day for 14 days lowered total testosterone (p = 0.03), and free testosterone was lower than with the flour placebo (p = 0.005). Estradiol, SHBG and albumin did not change [3].
- Population
- 24 resistance-trained men [3].
- Sources
- [3]
- Caveats
- The 12-week trial at the same dose found no change in testosterone [4].
How it compares with the reference method
Did not match the reference method2
Differences between dye methods and laboratories
Limited evidence: one comparison found the bromcresol green method read 0.35 g/dL higher than electrophoresis, most at low albumin, and laboratories in England differed widely.
The numbers and sources
- Compared with
- Capillary zone electrophoresis on the same samples, and results from other laboratories
- Effect
- On 165 serum samples, the bromcresol green method read a mean 3.54 g/L (0.35 g/dL) higher than capillary zone electrophoresis, the bromcresol purple method agreed with electrophoresis to within 1 g/L, and the gap between the two dye methods was larger at lower albumin. The excess with bromcresol green rose with alpha-1-globulin and C-reactive protein [13]. Across 1,079,193 primary care results in England, the variation between laboratories was large and potentially clinically significant. Mean albumin peaked at around age 20 and then fell with age, faster in women until about 60 [14]. Both US survey manuals above used bromcresol purple, and the Croatian pregnancy study used bromcresol green [2][4][5].
- Population
- 165 serum samples [13]. 1,079,193 albumin reports sent to primary care in England over 3 weeks [14].
- Sources
- [13], [14], [2], [4], [5]
- Caveats
- One method comparison at one laboratory. The authors of the English study conclude that reference intervals for albumin are to be stratified by age and sex and set by each laboratory until methods are standardized [14]. A laboratory report does not usually say which dye was used.
As a measure of nutrition
A US nutrition society position paper states albumin reflects inflammation and the risk of poor outcomes, not nutrition status or muscle mass.
The numbers and sources
- Compared with
- Nutrition status and protein-energy malnutrition
- Effect
- The American Society for Parenteral and Enteral Nutrition states that albumin and prealbumin characterize inflammation and do not describe nutrition status or protein-energy malnutrition. In illness the liver reprioritizes protein synthesis and albumin moves out of the bloodstream as capillaries become more permeable, so serum levels fall. The paper states that there is an association between inflammation and malnutrition but not between malnutrition and these protein levels, and that the proteins correlate with risk of adverse outcomes [15].
- Population
- A position paper approved by the society's board of directors, drawing on published literature. It reports no new patient data [15].
- Sources
- [15]
- Caveats
- A position paper, not a study with a stated accuracy figure. Its conclusion matches the cohort finding above that the link between albumin and heart disease weakened after adjustment for an inflammation marker [10].
What studies tie it to
Linked in research3
Death from any cause
Linked to more deaths at lower albumin, with the odds of death 24% to 56% higher for each 0.25 g/dL lower in a review of cohort studies.
The numbers and sources
- Effect
- A review of cohort studies in people with and without illness found that albumin was inversely related to the risk of death in a graded manner over its entire range. The estimated increase in the odds of death was 24% to 56% for each 2.5 g/L (0.25 g/dL) lower albumin, and the association covered cardiovascular death as well as death overall [7]. In a meta-analysis of 90 cohort studies of acutely ill patients, each 10 g/L (1 g/dL) decline in albumin raised the odds of death by 137% and of complications by 89%, and the association appeared independent of nutritional status and inflammation [8].
- Population
- Cohort studies of many populations, from people with no known illness to patients with acute or chronic illness [7]. 291,433 acutely ill patients in 90 cohort studies [8].
- Sources
- [7], [8]
- Caveats
- Observational. The review's authors consider it likely that albumin is a highly sensitive indicator of preclinical disease and disease severity, and state that there is no direct evidence that albumin itself protects [7].
Death and complications after surgery
One US veterans cohort linked lower albumin before surgery to more deaths within 30 days, from under 1% above 4.6 g/dL to 29% below 2.1 g/dL.
The numbers and sources
- Effect
- A fall in albumin from above 46 g/L (4.6 g/dL) to below 21 g/L (2.1 g/dL) was associated with an exponential rise in 30-day mortality from less than 1% to 29% and in complications from 10% to 65%. Among 62 preoperative variables, albumin was the strongest predictor of death and complications, and it predicted sepsis and major infections more closely than other complications [9].
- Population
- 54,215 major noncardiac surgery cases at 44 Veterans Affairs medical centers [9].
- Sources
- [9]
- Caveats
- Observational, one cohort, published in 1999. It does not show that raising albumin before surgery changes the outcome.
Heart disease and stroke
Linked to more cardiovascular disease at lower albumin, about 85% more for each 1 g/dL lower in a meta-analysis of 14 studies.
The numbers and sources
- Effect
- In a Danish general population cohort, the hazard ratio for each 10 g/L (1 g/dL) lower albumin was 1.17 (95% CI 1.08 to 1.28) for ischemic heart disease, 1.25 (1.09 to 1.43) for heart attack, 1.37 (1.21 to 1.54) for any stroke and 1.46 (1.28 to 1.68) for ischemic stroke. In the accompanying meta-analysis, the risk ratio for a cardiovascular event per 10 g/L lower albumin was 1.85 (95% CI 1.39 to 2.47), with the Danish cohort carrying 57% of the weight [10].
- Population
- 100,520 people without prior cardiovascular disease followed for a median of 8.5 years, and 150,652 individuals in 14 studies [10].
- Sources
- [10]
- Caveats
- Observational. The estimates weakened after adjustment for C-reactive protein, and the authors write that the association is partly explained by albumin falling during inflammation [10].
Checked, no link found1
Raising albumin by infusion
Not shown to lower deaths: two trials that raised albumin to 3.0 g/dL or more by infusion, in sepsis and in cirrhosis, found no benefit.
The numbers and sources
- Effect
- In severe sepsis, albumin infusion to a target of 30 g/L (3.0 g/dL) or more did not change death at 28 days (31.8% against 32.0% with crystalloid alone, RR 1.00, 95% CI 0.87 to 1.14) or at 90 days (41.1% against 43.6%, RR 0.94, 0.85 to 1.05) [11]. In hospitalized patients with decompensated cirrhosis and albumin below 30 g/L, infusions that raised albumin to 30 g/L or more did not change a composite of new infection, kidney dysfunction or death (29.7% against 30.2% with standard care, adjusted OR 0.98, 95% CI 0.71 to 1.33), and more severe or life-threatening serious adverse events occurred in the albumin group [12]. An earlier meta-analysis of 9 controlled trials of correcting low albumin was inconclusive [8].
- Population
- 1,818 patients with severe sepsis in 100 intensive care units [11]. 777 hospitalized patients with decompensated cirrhosis [12]. 535 patients in 9 trials [8].
- Sources
- [11], [12], [8]
- Caveats
- Both large trials were open-label and enrolled people who were seriously ill, so they do not address albumin that is low for other reasons [11][12].
Sources
- US Food and Drug Administration. 21 CFR 862.1035, Albumin test system. Electronic Code of Federal Regulations. https://www.ecfr.gov/current/title-21/section-862.1035
- Centers for Disease Control and Prevention, National Center for Health Statistics. National Health and Nutrition Examination Survey 2017-2018 Laboratory Procedure Manual: Albumin, serum, Roche Cobas 6000. Performed by the University of Minnesota Advanced Research and Diagnostic Laboratory. https://wwwn.cdc.gov/nchs/data/nhanes/public/2017/labmethods/BIOPRO-J-MET-Albumin-508.pdf
- Centers for Disease Control and Prevention, National Center for Health Statistics. National Health and Nutrition Examination Survey 2017-2018 Data Documentation, Codebook, and Frequencies: Standard Biochemistry Profile (BIOPRO_J). February 2020. https://wwwn.cdc.gov/Nchs/Data/Nhanes/Public/2017/DataFiles/BIOPRO_J.htm
- Centers for Disease Control and Prevention, National Center for Health Statistics. National Health and Nutrition Examination Survey 2015-2016 Laboratory Procedure Manual: Albumin, refrigerated serum, Beckman UniCel DxC 800 Synchron. Performed by Collaborative Laboratory Services. https://wwwn.cdc.gov/nchs/data/nhanes/public/2015/labmethods/BIOPRO_I_MET_ALBUMIN_DXC800.pdf
- Šupak-Smolčić V, Franin L, Antončić D, et al. Reference Intervals for Common Biochemistry and Hematology Parameters in Early Pregnancy: A Prospective Study. Diagnostics. 2025. https://doi.org/10.3390/diagnostics15040415
- Bacq Y, Zarka O, Bréchot JF, et al. Liver function tests in normal pregnancy: A prospective study of 103 pregnant women and 103 matched controls. Hepatology. 1996. https://doi.org/10.1002/hep.510230514
- Goldwasser P, Feldman J. Association of serum albumin and mortality risk. Journal of Clinical Epidemiology. 1997. https://doi.org/10.1016/S0895-4356(97)00015-2
- Vincent JL, Dubois MJ, Navickis RJ, Wilkes MM. Hypoalbuminemia in Acute Illness: Is There a Rationale for Intervention? A Meta-Analysis of Cohort Studies and Controlled Trials. Annals of Surgery. 2003. https://doi.org/10.1097/01.sla.0000055547.93484.87
- Gibbs J, Cull W, Henderson W, et al. Preoperative Serum Albumin Level as a Predictor of Operative Mortality and Morbidity: Results From the National VA Surgical Risk Study. Archives of Surgery. 1999. https://doi.org/10.1001/archsurg.134.1.36
- Ronit A, Kirkegaard-Klitbo DM, Dohlmann TL, et al. Plasma Albumin and Incident Cardiovascular Disease: Results From the CGPS and an Updated Meta-Analysis. Arteriosclerosis, Thrombosis, and Vascular Biology. 2020. https://doi.org/10.1161/ATVBAHA.119.313681
- Caironi P, Tognoni G, Masson S, et al. Albumin Replacement in Patients with Severe Sepsis or Septic Shock. New England Journal of Medicine. 2014. https://doi.org/10.1056/NEJMoa1305727
- China L, Freemantle N, Forrest E, et al. A Randomized Trial of Albumin Infusions in Hospitalized Patients with Cirrhosis. New England Journal of Medicine. 2021. https://doi.org/10.1056/NEJMoa2022166
- Garcia Moreira V, Beridze Vaktangova N, Martinez Gago MD, et al. Overestimation of Albumin Measured by Bromocresol Green vs Bromocresol Purple Method: Influence of Acute-Phase Globulins. Laboratory Medicine. 2018. https://doi.org/10.1093/labmed/lmy020
- Weaving G, Batstone GF, Jones RG. Age and sex variation in serum albumin concentration: an observational study. Annals of Clinical Biochemistry. 2016. https://doi.org/10.1177/0004563215593561
- Evans DC, Corkins MR, Malone A, et al. The Use of Visceral Proteins as Nutrition Markers: An ASPEN Position Paper. Nutrition in Clinical Practice. 2021. https://doi.org/10.1002/ncp.10588