Prealbumin (Transthyretin): Normal Range, Results & What The
Everything you need to know about Prealbumin (Transthyretin): Normal Range, Results & What The test results, including normal ranges and what abnormal levels might mean.
Reference Range
Unit: mg/dLReference Range
Reference ranges vary by laboratory. Always consult your healthcare provider for interpretation of your specific results.
What is Prealbumin?
Prealbumin (now called transthyretin) is like a real-time nutritional status monitor. Unlike albumin, which has a half-life of about 20 days and reflects long-term protein status, prealbumin turns over every 2-3 days. This short half-life makes it exquisitely sensitive to recent changes in nutrition and acute illness.
Despite its name, prealbumin isn't related to albumin at all. It's a transport protein produced by the liver that carries thyroid hormone and vitamin A. The "pre" in its name comes from older lab techniques where it migrated ahead of albumin on electrophoresis gels—a historic artifact that persists in medical terminology.
Think of prealbumin as a quick feedback tool. When you're nutritionally replete and healthy, prealbumin stays in the normal range. When protein intake drops, malnutrition develops, or inflammation increases, prealbumin falls within days. This rapid response makes it valuable for monitoring nutritional support in hospitalized patients and tracking recovery.
The Inflammation Trap
Prealbumin is a negative acute phase reactant—meaning levels drop during inflammation, regardless of nutritional status. A sick patient with excellent nutrition can have very low prealbumin simply due to inflammation. Always check CRP or ESR alongside prealbumin to distinguish malnutrition from inflammatory effects.
Understanding Your Results
Prealbumin is measured in milligrams per deciliter (mg/dL):
Understanding Your Results (mg/dL)
Excellent nutritional status—adequate protein intake
Standard reference range—good status
Mild depletion or inflammation—interpret with context
Significant depletion—nutritional support often needed
Severe depletion—aggressive nutritional intervention
Rare—possible steroid use, kidney dysfunction, or dehydration
Why Prealbumin Levels Change
Prealbumin changes reflect nutritional status, inflammation, or protein loss:
Causes of Abnormal Prealbumin
| Factor | Effect | What to Do |
|---|---|---|
| Protein-calorie malnutrition | Decreases | Inadequate protein or calorie intake causes liver to decrease prealbumin production. This occurs in starvation, eating disorders, poor dietary intake, and malabsorption. Treatment: nutritional assessment and intervention. Increase protein intake (1.2-1.5 g/kg/day), ensure adequate calories. Prealbumin rises within days of adequate nutrition—use it to monitor response to feeding. |
| Acute inflammation or infection | Decreases | Prealbumin is a negative acute phase reactant—inflammation rapidly decreases levels regardless of nutritional status. Cytokines (IL-6) suppress liver production. This is why CRP must be checked with prealbumin. During acute illness, low prealbumin doesn't equal malnutrition. Wait until inflammation resolves (CRP normal) before assessing nutritional status. |
| Liver disease | Decreases | Liver synthesizes prealbumin. Advanced liver disease (cirrhosis, hepatitis) reduces production. Low prealbumin reflects impaired synthetic function, not necessarily malnutrition. Treatment: address underlying liver disease. Nutritional support still important but prealbumin may not normalize until liver function improves. Correlate with other liver tests (albumin, INR, bilirubin). |
| Protein-losing states (nephrotic syndrome, IBD) | Decreases | Prealbumin is lost in urine (nephrotic syndrome) or gastrointestinal tract (protein-losing enteropathy, IBD). Losses exceed production capacity, causing levels to fall. Treatment: address underlying condition. Nephrotic syndrome may need ACE inhibitors, immunosuppression. IBD needs disease control. Nutritional support helps offset losses but won't normalize until protein loss stops. |
| High-dose corticosteroids | Increases | Steroids increase prealbumin synthesis, causing paradoxically high levels despite possible poor nutrition. This effect doesn't reflect true nutritional status. If on steroids, interpret prealbumin cautiously and rely more on clinical assessment and other markers. The steroid effect is dose-dependent and resolves when steroids are stopped. |
Always tell your doctor about medications, supplements, and recent health events before testing.
The Malnutrition vs. Inflammation Distinction
Distinguishing true malnutrition from inflammatory effects is crucial:
When Prealbumin Patterns Guide Management
Specific prealbumin patterns combined with clinical context reveal different conditions:
Prealbumin Patterns and Their Meaning
Prealbumin must be interpreted with CRP, clinical status, and nutritional intake.
Low prealbumin with normal CRP and poor intake
True malnutrition. Prealbumin is low because of inadequate protein/calorie intake. Common in elderly, eating disorders, chronic illness, poverty, hospitalization. Treatment: nutritional intervention—protein supplements, oral nutritional supplements, possibly feeding tube if severe. Prealbumin rises within days of adequate nutrition, making it excellent for monitoring response.
Low prealbumin with high CRP during acute illness
Inflammatory suppression, not malnutrition. Cytokines inhibit prealbumin production. Low prealbumin during acute infection, surgery, trauma doesn't equal malnutrition. Don't overfeed based on low prealbumin alone. Treat underlying inflammation. Reassess prealbumin after CRP normalizes to determine true nutritional status.
Prealbumin rising while CRP falling
Recovery pattern. As inflammation resolves, prealbumin production resumes. Rising prealbumin with falling CRP indicates resolving illness and adequate nutrition. This is the expected trajectory during recovery. Continue current nutritional support. Prealbumin typically rises 1-2 mg/dL per day with adequate nutrition.
Prealbumin normal with no clinical concerns
Normal pattern. Adequate nutritional status, no significant inflammation. Continue balanced diet with adequate protein (0.8-1.0 g/kg/day for healthy adults). No specific intervention needed. Prealbumin monitoring is generally not required for healthy people eating normally.
Your Action Plan Based on Results
If your prealbumin is optimal (22-40 mg/dL):
- Excellent nutritional status
- Adequate protein intake
- Maintain healthy nutrition:
- Balanced diet with quality protein sources
- Adults: 0.8-1.0 g/kg protein daily
- More if active or elderly (1.0-1.2 g/kg)
- No specific intervention needed
If your prealbumin is mildly low (15-17 mg/dL):
- Mild depletion or inflammation
- Check CRP level
- If CRP normal:
- Assess nutritional intake
- Increase protein intake to 1.2-1.5 g/kg/day
- Consider protein supplements
- Address any barriers to eating (dental, appetite, access)
- If CRP elevated:
- Inflammation likely contributing
- Treat underlying cause
- Reassess prealbumin after inflammation resolves
- Repeat testing in 1-2 weeks
If your prealbumin is moderately low (10-14 mg/dL):
- Significant depletion
- Medical evaluation recommended
- Comprehensive assessment:
- CRP level
- Nutritional intake assessment
- Weight history
- Signs of malnutrition
- Liver and kidney function
- Treatment plan:
- Registered dietitian consultation
- Protein intake 1.5-2.0 g/kg/day
- Oral nutritional supplements
- Address underlying causes
- Monitor prealbumin trend
- Expect 2-3 mg/dL rise per day with adequate nutrition
If your prealbumin is severely low (＜10 mg/dL):
- Severe depletion
- Aggressive nutritional intervention often needed
- Possible interventions:
- Oral nutritional supplements (high-protein, high-calorie)
- Food fortification
- Multiple small meals
- Enteral nutrition (tube feeding) if unable to eat adequately
- Parenteral nutrition (IV) if GI not functional
- Monitor:
- Prealbumin every 3-7 days
- Weight trends
- Clinical improvement
- Specialist consultation (nutrition support team) often helpful
If prealbumin is high (＞45 mg/dL):
- Rare and usually not nutritional
- Consider:
- Recent or current steroid use
- Kidney dysfunction
- Dehydration
- Evaluate:
- Medication review
- Kidney function tests
- Hydration status
- No specific treatment needed for high prealbumin itself
The Steroid Effect
High-dose corticosteroids (prednisone, methylprednisolone) increase prealbumin synthesis, causing levels to rise regardless of nutritional status. A patient on high-dose steroids may have normal or high prealbumin despite significant malnutrition. Always interpret prealbumin in the context of medications. In steroid-treated patients, rely more on clinical assessment, weight trends, and intake records than prealbumin alone.
Common Questions
Track Your Prealbumin Results
Monitor your levels over time, identify trends, and share your history with your doctor.