Background

This is the most of all proteins present in human blood with about 50-60% and it is known as human serum albumin (HSA). It is synthesized by hepatocytes of liver, hence its structure is linear, because this protein is monomeric and soluble in water. This makes it a fast acting protein hence constituting half of the total plasma proteins found in circulation. Serum albumin binds many ligands both endogenous and exogenous materials for up take by the body. It carries drugs such as propranolol, thiopental, methadone, fatty acids, warfarin and furosemide among other endogenous and exogeneous ligands. This way it helps to maintain plasma oncotic pressure. 

Upon entering blood vessels about 30-40% of the albumin remains inside while the rest moves out into interstitial space. Renourishment of majority of proteins that leak out into tissues outside circulation occurs through lymphatics back into systemic blood vessels. Albumin has a duration time to pass through circulation lasting 16 hours or more. 

Different methods like electrophoresis, dye binding techniques, urine dipstick and chemiluminescence assay are used to determine albumin levels in various ways. 

Indications/Applications

Some of the indications that necessitate conducting an albumin test are kidney disease and liver disease. 

The albumin test is done under the following conditions: 

Brain Tumor 

Prolonged dysentery 

Loss of weight 

Cirrhosis 

Nephrotic syndrome symptoms include Kidney or liver functioning related symptoms are a reason for undergoing this particular kind of examination. 

The occurrence of which should lead to an albumin test includes if you have experienced such symptom as: 

Darkened urine Itchy skin especially during pregnancy 

Stool like gray or pale coloration indicating lightening feces 

Yellow skin due to jaundice caused by bilirubin accumulation 

Discomfort on the right side below ribs or soreness around right ribs 

Fever 

Frequent urination especially at night time 

Dyspnoea or shortness of breath upon mild exertion (orthopnoea) 

Vomiting and nausea 

The albumin test has its own limitations namely: Perform this alongside blood urea nitrogen and creatinine tests. Albumin level is low in pregnant women. Prealbumin measurement is necessary to check for nutritional status. Patients who receive large amounts of intravenous fluids would require more accurate results. There could be significant lipemia affecting the accuracy of albumin value. 

A retrospective review involving two hundred twenty-nine patients demonstrated that the frequency of significant complications from cirrhosis is highly associated with progression of liver fibrosis, albumin and prothrombin time. The researchers cited decreased albumin levels in the circulation as a significant factor observed in 0.04 g/dL/year for patients who had serious problems, but 0.38 g/dL per year for those with hepatic failure and 0.25 g/dL per year among individuals suffering from gastroesophageal varices; this drop was found to be the only predictor of any event in multivariate analysis. This further indicates the need for effective antiviral therapies that will bring down cases of severe NAFLD outcomes. 

Clinical Significance: 

In patients with different liver diseases serum albumin becomes a major criterion that reflecting liver synthesis activities being more elevated under various pathologic conditions. Albumin occurring hypoalbuminemia usually result from increased catabolism secondary to high fever, infection, trauma, burns, surgery, cancer chemotherapy and major illness. Treating these patients requires a comprehensive evaluation of all aspects including clinical findings. In a fasting clinicians can expect hypoalbuminemia from malnourished patients, as their albumin levels may be reduced by one-third within 24 to 48 hours of fasting that quickly normalises after the patient is replenished. Albumin is applied to evaluation of malnutrition and clinical readiness for anesthesia and is useful in detection and assessment of patients with anasarca and malabsorption. 

The inflammatory disorders can be responsible for decreasing the albumin synthesis, increasing breakdown, and enhancing increased in the vascular permeability. On top of that, albumin helping with the diagnosis of abnormal peritoneal fluid accumulations, like ascites, which can be a result of different underlying disorders. 

Reference Range

The normal range of albumin in serum is 3.5 g/dL to 5.5 g/dL. 

This range may vary from laboratory to laboratory. 

Interpretation

• Reduced level of albumin can indicate conditions like: 
• Kidney disease 
• Ascites 
• Glomerulonephritis 
• Burns 
• Liver disease (severe cirrhosis, fatty liver disease, hepatitis) 
• Infection 
• Malabsorption syndromes (Crohn’s disease, Whipple disease, celiac disease) 
• Thyroid disease 
• Malnutrition 
• Additional conditions include: 
• Wilson disease 
• Nephropathy 
• Hepatorenal syndrome 
• Hepatic encephalopathy 
• Sprue 
• Elevated level of albumin may lead to condition like intense diarrhea which cause dehydration. 

Collection And Panels

• Collection: 
• Specimen type: Blood 
• Collection: 4 mL blood in lime green tube or gold SST tub 
• Storage requirements: Refrigerate serum/plasma 
• Panels: 
• Comprehensive metabolic panel (CMP) 
• Liver panel (LPP) 
• Renal function panel (RFP) 

References

https://www.ncbi.nlm.nih.gov/books/NBK459198/ 

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8341320/