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Free Fructosamine (Serum)

Published: August 9, 2026Updated: August 16, 2026

This test measures the average blood sugar levels over the past 2–3 weeks by tracking glycated proteins, specifically free fructosamine, in your serum.

Quick summary

["Helps assess long-term blood sugar control beyond just a single glucose reading."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
59238-6
Short code
PSA Free MFr Fld
Synonyms
PSA Free MFr Fld
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Ref low
0
Ref high
4
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
84153
SNOMED
39392002
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

Why It’s Used

Doctors may order this test if you have diabetes or prediabetes to monitor how well your blood sugar is managed over time. It’s particularly useful when glucose levels fluctuate or when monitoring long-term glycemic control in patients with chronic conditions like diabetes.

How It Works

Blood is drawn and sent to a lab where it’s analyzed using an immunoassay method. This test measures the amount of free fructosamine, a form of sugar-protein bond that reflects your average blood sugar levels over weeks.

What to Expect

You’ll receive a standard blood draw, typically from your arm. Results are usually available within a few days. Unlike hemoglobin A1c, this test doesn’t require fasting.

Normal vs. Abnormal Results

While reference ranges can vary by lab, higher levels may indicate poor blood sugar control, while lower levels could suggest consistently low blood sugar or certain metabolic conditions.

Reference range

Normal: <4.0 ng/mLN/A

Specimen: serum

No special preparation required. For PSA, avoid sexual activity for 24-48 hours before the test.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Free fructosamine provides a snapshot of your blood sugar management over a longer period than a single glucose test. It’s especially valuable for patients with diabetes who experience frequent blood sugar swings or those who can’t fast for a hemoglobin A1c test. However, it’s less commonly used than hemoglobin A1c due to less standardization in results.

Short name

Free Fructosamine

Frequently asked questions

What does a high free fructosamine level mean?
A high level suggests your blood sugar has been consistently elevated over the past few weeks, which could indicate poor diabetes management or other conditions affecting blood sugar control.
Can I fast before this test?
No, fasting is not required for this test. It measures your average blood sugar levels regardless of when you last ate.
How often should I get this test?
Your doctor will determine the frequency based on your health needs. Typically, it may be used alongside other tests like hemoglobin A1c to monitor long-term blood sugar trends.
  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 16, 2026. · Read our editorial policy