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Total Plasma Transferrin Saturation (with Donor Comparison)

Published: August 9, 2026Updated: August 14, 2026

This test measures how much iron your plasma can bind, compared to a reference donor sample, to assess iron metabolism and potential iron deficiency or overload.

Quick summary

["Iron levels in your blood may affect how well your body functions, especially if you have anemia or other health conditions."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 14, 2026Editorial policy

Key facts at a glance

LOINC
99786-6
Short code
cfDNA-D/T Lung
Synonyms
cfDNA.donor/cfDNA.total p lung trnsplt
Category
chemistry
Sample
plasma
Container
Streck Cell-Free DNA BCT tube (or equivalent cfDNA preservation tube); EDTA plasma tubes are not optimal for cfDNA stability
Units
N/A
Ref low
0.5
Ref high
1
Critical range
— – 1 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
Next-generation sequencing (NGS) or quantitative PCR (qPCR) for single nucleotide polymorphism (SNP) analysis to calculate donor-derived cell-free DNA fraction
CPT
81479
SNOMED
446080008
Specimen volume
8-10 mL of whole blood collected in cfDNA stabilization tube; minimum 4 mL
Stability
Ambient: up to 7 days with cfDNA stabilization tube (e.g., Streck BCT). Plasma separated and frozen at -80°C: up to 30 days. Avoid repeated freeze-thaw cycles.
Hemolysis max
100
Lipemia max
100
Icterus max
50
TAT
48–168 hours
Order
routine

What This Test Measures

Transferrin is a protein in your blood that carries iron. This test evaluates the percentage of transferrin that is saturated with iron. By comparing your plasma transferrin saturation to a donor’s sample, doctors can better identify iron-related issues, such as iron deficiency or iron overload, which can impact your overall health.

Why It Matters in Your Health

Iron is essential for making red blood cells and maintaining energy levels. If your body doesn’t have enough iron, you may develop anemia, fatigue, or other symptoms. If you have too much iron, it can cause damage to organs over time. This test helps doctors determine whether your iron levels are within a healthy range.

When You Might Need This Test

Your doctor may order this test if you have symptoms like fatigue, weakness, or unexplained anemia. It may also be used in patients with chronic diseases (like kidney disease or liver disease), those undergoing blood transfusions, or individuals with a history of iron-related disorders.

What to Expect Before the Test

No special preparation is needed for this test. A blood sample will be drawn from a vein in your arm, similar to other routine blood tests. The process is quick and usually painless.

Reference range

Donor-derived cfDNA fraction (donor/total cfDNA) is reported as a percentage. Stable lung transplant recipients typically have values <0.5-1.0%. Values above the established threshold may suggest acute rejection.N/A

Specimen: plasma

No fasting required. Patient should be well-hydrated. Inform the laboratory of recent blood transfusions, as they may temporarily increase total cfDNA. The test should be performed at standardized intervals post-transplant as directed by the transplant center.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Elevated transferrin saturation may indicate iron overload, which can be linked to conditions like hemochromatosis or excessive iron intake. Low transferrin saturation often suggests iron deficiency, which can be caused by poor diet, blood loss, or malabsorption. This test helps guide treatment, such as dietary changes, supplements, or blood transfusions.

Frequently asked questions

What does a low transferrin saturation result mean?
A low transferrin saturation result suggests your body may not be absorbing enough iron or you could have iron deficiency. This could be due to factors like poor diet, heavy menstrual bleeding, or gastrointestinal issues. Your doctor may recommend dietary adjustments, iron supplements, or further testing to determine the cause.
What does a high transferrin saturation result mean?
A high transferrin saturation result may indicate iron overload, which can be harmful if left untreated. This could be caused by conditions like hemochromatosis (a genetic disorder), excessive red meat consumption, or frequent blood transfusions. Your doctor may suggest lifestyle changes, blood donation, or medications to manage iron levels.
How often should I get this test?
The frequency of this test depends on your health condition and medical history. If you have a known iron-related disorder, your doctor may recommend regular monitoring. Otherwise, this test is usually ordered only when symptoms or other test results suggest a need for evaluation.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 14, 2026. · Read our editorial policy