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Glucose in Serum or Plasma (Mass Concentration)

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

This test measures the amount of glucose (sugar) in your blood drawn from a vein.

Quick summary

["Your doctor may check this to monitor blood sugar levels, especially if you have diabetes or other health conditions."]

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

Key facts at a glance

LOINC
46404-0
Short code
GH 2h p Ins IV SerPl-mCnc
Synonyms
GH 2h p Ins IV SerPl-mCnc
Category
hormone
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
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 Is This Test Done?

Doctors order this test to assess blood sugar levels, diagnose diabetes or prediabetes, monitor treatment for diabetes, check for low blood sugar (hypoglycemia), or evaluate conditions like kidney disease or liver problems that can affect glucose metabolism.

What to Expect Before the Test

No special preparation is needed, but you may be asked to fast (not eat or drink) for 8–12 hours before the test if it’s part of a fasting glucose panel. Bring any medications you’re taking and let your doctor know about allergies or conditions.

How the Test Is Performed

A healthcare provider will insert a small needle into a vein (usually in your arm) to draw blood. You may feel a slight pinch, but it’s over quickly. The blood is sent to a lab for analysis.

What the Results Mean

Results are typically reported in milligrams per deciliter (mg/dL). Your doctor will compare your result to your individual reference range and clinical picture. High or low values may trigger further testing or adjustments to treatment.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Glucose levels outside normal ranges can signal diabetes, insulin resistance, or metabolic disorders. Persistently high glucose may indicate poor blood sugar control, while dangerously low levels can cause weakness, dizziness, or confusion. This test is foundational for managing these conditions and guiding treatment decisions.

Short name

Serum/Plasma Glucose

Frequently asked questions

What causes abnormal glucose levels?
Abnormal glucose levels can result from diet (eating too much sugar or skipping meals), physical activity, certain medications (like steroids or diabetes drugs), infections, or underlying health conditions like diabetes, kidney disease, or thyroid disorders.
How long does it take to get results?
Results are usually available within 1–2 business days, depending on lab processing times. Your doctor will contact you if additional follow-up is needed.
Can I eat or drink before this test?
If fasting is required (e.g., for a fasting glucose test), avoid food and liquids except water for 8–12 hours beforehand. For non-fasting tests, eat normally, but check with your doctor to confirm.
  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