Tube, E.S.R.

Quick Answer: The Tube, E.S.R. is a narrow graduated tube used to measure the erythrocyte sedimentation rate, the distance red blood cells fall in anticoagulated blood standing upright for one hour. An ESR tube is used in haematology practicals and laboratories for this simple, widely taught blood test.

How the ESR Test Works

When anticoagulated blood stands in a vertical tube, the red cells slowly sink and leave a column of clear plasma above them. The height of that plasma column after exactly one hour, read in millimetres, is the ESR. Red cells settle faster when they stack together into rouleaux, and that stacking increases when plasma contains more fibrinogen and other proteins produced in inflammation. The ESR is therefore a non-specific marker: it rises in infections, inflammatory conditions and some other diseases, but it cannot identify the cause on its own.

Two classic methods use different tubes. The Westergren method uses a long, narrow tube filled with blood diluted with sodium citrate, and is the usual reference method. The Wintrobe method uses a shorter tube filled with EDTA blood, which can also be centrifuged afterwards to read the packed cell volume. In both, the tube must stand exactly vertical in a rack, away from vibration, draughts and direct sunlight, because tilting and warmth speed up settling and give falsely high readings.

The listing does not state which type this tube is, its length or scale, or whether it is glass or plastic. A rack that holds tubes vertically is needed for the test. Blood samples for other haematology practicals are often spun in a glass centrifuge tube.

Safe Handling of Blood Samples

• Treat every blood sample as potentially infectious: wear gloves, never pipette by mouth and work on a surface that can be disinfected.
• Keep the ESR tube exactly vertical and read it at exactly 60 minutes.
• Decontaminate reusable tubes in disinfectant before washing, rinse thoroughly and dry them completely, since water or detergent residue affects results.
• Dispose of single-use tubes and blood waste according to your institution’s biomedical waste rules.

Applications

• Medical laboratory technology practicals on the ESR test
• Demonstrating rouleaux formation and the effect of plasma proteins in physiology classes
• Routine ESR measurement in teaching hospital and college laboratories
• Comparing Westergren and Wintrobe methods in haematology training

Specifications

Why Choose LabEquip

Medical laboratory technology colleges, nursing schools and hospital teaching labs use ESR tubes in quantity for haematology practicals. LabEquip lists them in Biology Lab Products; tell us which method and rack you use through the contact page.

Frequently Asked Questions

What does the ESR test measure?

It measures how far red blood cells settle in one hour in a vertical tube of anticoagulated blood. The result, in millimetres per hour, rises when inflammation increases plasma proteins such as fibrinogen.

What is the difference between Westergren and Wintrobe tubes?

The Westergren tube is longer, uses citrate-diluted blood and is the usual reference method. The Wintrobe tube is shorter, uses undiluted EDTA blood and can also be used to read the packed cell volume.

Why must the tube stand exactly vertical?

Even a slight tilt lets red cells slide down the wall and settle faster, giving a falsely high ESR. A proper ESR rack keeps each tube upright.

What factors can give a false result?

Tilted tubes, high room temperature, vibration, clotted samples, delays before setting up the test and the wrong ratio of blood to anticoagulant can all distort the reading.

Is a high ESR a diagnosis?

No. It is a non-specific sign that inflammation or another process is present. Doctors interpret it together with symptoms, examination and other tests.

Which type of ESR tube is this?

The listing does not say whether it is a Westergren or Wintrobe tube, nor its material or scale, so confirm the type when you enquire.

Last Updated: September 2026