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Red Blood Cell Sedimentation Rate (Manual Method) – Plasma

Published: August 9, 2026Updated: August 17, 2026

This test measures how quickly red blood cells settle in plasma over time, often used to assess inflammation or blood viscosity.

Quick summary

["The sedimentation rate helps doctors check for conditions like infections, autoimmune diseases, or other inflammatory processes."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 17, 2026Editorial policy

Key facts at a glance

LOINC
16828-6
Short code
RBC # Semin plas Manual
Synonyms
RBC # Semin plas Manual
Category
chemistry
Sample
plasma
Container
Lavender-top (EDTA) or Green-top (Heparin)
Units
N/A
Ref low
4.2
Ref high
5.9
Critical range
2 N/A – 7 N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
manual-count
CPT
85041
SNOMED
900000000000003001
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

What This Test Measures

The manual sedimentation rate evaluates how red blood cells (RBCs) clump together and sink to the bottom of a tube of plasma over a set period. This process, called erythrocyte sedimentation rate (ESR), can reflect underlying inflammation or blood abnormalities.

Why It’s Done

Your doctor may order this test to monitor conditions like rheumatoid arthritis, lupus, infections, or other inflammatory diseases. It can also help assess blood disorders or diagnose conditions affecting red blood cell behavior.

How It Works

A small sample of your blood is placed in a tube with an anticoagulant. The plasma is carefully removed, leaving only the red blood cells. The tube is tilted at a slight angle, and the time it takes for the cells to settle is measured manually.

What to Expect Before the Test

No special preparation is needed, but inform your doctor if you’re taking blood-thinning medications or have recently had a blood transfusion, as these can affect results.

Reference range

Adult males: 4.2-5.9; Females: 3.8-5.1 x 10^12/LN/A

Specimen: plasma

No special preparation required. Stay well hydrated.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Red Blood Cell Sedimentation Rate (Manual)

Frequently asked questions

How long does it take to get results?
Results are typically available within 1–2 business days, depending on lab processing times.
What does a high sedimentation rate mean?
A high sedimentation rate may suggest inflammation, infection, or autoimmune conditions. Your doctor will consider your symptoms and other test results to determine the cause.
Can diet or medications affect this test?
Certain medications (like blood thinners) or recent blood transfusions can influence results. Avoiding strenuous activity or dietary supplements that may alter blood composition before testing can help ensure accurate results.
  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 17, 2026. · Read our editorial policy