Capillary Tubes

<h2 dir="ltr">What are Capillary Tubes? </h2>
 Capillary tubes for laboratory use are thin-walled, open-ended tubes&mdash;typically 75 mm long with an internal diameter of 1.1&ndash;1.2 mm&mdash;that collect microvolume blood samples (40&ndash;80 &micro;L) by capillary action from finger-stick or heel-stick punctures, directly from anticoagulated blood collection tubes, or from blood gas analyzers. They are the primary consumables for the micro-hematocrit (packed cell volume, PCV) determination: tubes are filled, sealed, centrifuged at 10,000&ndash;14,500 RPM for 5 minutes, and the ratio of packed red cells to total blood column is read against a hematocrit chart. Globe Scientific manufactures both soda lime glass and plastic (unbreakable) micro-hematocrit capillary tubes, as well as pre-calibrated borosilicate glass tubes for blood gas applications. Choose heparinized capillary tubes for direct finger-stick collection from untreated blood; choose plain (untreated) tubes when filling from an anticoagulated blood collection tube.
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<h2 dir="ltr">What you will find:</h2>
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<ul>
<li dir="ltr" role="presentation">Glass capillary tubes for micro-volume liquid transfer</li>
<li dir="ltr" role="presentation">Heparinized capillary tubes for blood sample collection</li>
<li dir="ltr" role="presentation">Plain capillary tubes for general laboratory applications</li>
<li dir="ltr" role="presentation">Micro-hematocrit capillary tubes for blood analysis</li>
<li dir="ltr" role="presentation">Sealed-end and open-end capillary tubes for flexible workflows</li>
<li dir="ltr" role="presentation">Disposable precision-bore tubes for single-use sampling</li>
<li dir="ltr" role="presentation">Calibrated microcapillary tubes for consistent volume uptake</li>
<li dir="ltr" role="presentation">Thin-walled tubes for rapid capillary action filling</li>
<li dir="ltr" role="presentation">Sterile capillary tubes for diagnostic applications</li>
<li dir="ltr" role="presentation">General-purpose laboratory micro-sampling tubes</li>
</ul>
<h2 dir="ltr"> How to Choose Capillary Tubes</h2>
 Plain vs. Heparinized Plain capillary tubes (blue tip, Globe Scientific) are used when filling from a pre-anticoagulated specimen (EDTA or citrate blood collection tube). Heparinized tubes prevent clotting in samples collected directly from a skin puncture: ammonium heparin&ndash;coated tubes (green tip) and sodium heparin&ndash;coated tubes (red tip) are both available. The tip color is the universal identifier &mdash; confirm the coding convention with your supplier before ordering, as some manufacturers reverse the color assignments. Glass vs. Plastic Soda lime glass capillary tubes (Globe Scientific catalog 51602&ndash;51607) provide excellent capillary action, low surface adsorption, and superior optical clarity for reading the hematocrit column. Plastic capillary tubes (catalog 51620) eliminate the sharps hazard from glass breakage during centrifugation&mdash;a significant occupational safety consideration for high-volume clinical labs processing hundreds of hematocrit determinations daily. Both formats fit standard 75 mm hematocrit centrifuges. Pre-Calibrated (Blood Gas) Tubes Pre-calibrated borosilicate glass capillary tubes (Globe Scientific catalog 51628, I.D. 0.55 mm &plusmn; 0.03 mm) are precision-ground for blood gas and co-oximetry analyzers requiring specific internal volume tolerance. These differ from standard hematocrit tubes in inner diameter; using the wrong tube in a blood gas analyzer causes instrument error codes and inaccurate analyte results. Centrifuge Compatibility All 75 mm micro-hematocrit capillary tubes are compatible with standard hematocrit centrifuges rated for 10,000&ndash;14,500 RPM. Confirm your centrifuge head accepts the tube O.D. (1.5 mm &plusmn; 0.05 mm for Globe Scientific glass tubes) before ordering in bulk.
<h2 dir="ltr"> Specifications Context</h2>
 Globe Scientific soda lime glass micro-hematocrit capillary tubes have an I.D. of 1.15 mm &plusmn; 0.05 mm, O.D. of 1.5 mm &plusmn; 0.05 mm, and a length of 75 mm &plusmn; 1 mm, with a fill volume of approximately 75 &micro;L. The standard centrifugation protocol is 10,000&ndash;14,500 RPM for 5 minutes in a dedicated hematocrit centrifuge. Normal hematocrit ranges: 38&ndash;50% for adult males, 35&ndash;47% for adult females; values outside this range, combined with elevated ESR and other CBC parameters, are used to evaluate anemia, polycythemia, and inflammatory conditions. As of 2026, Globe Scientific is an ISO 9001:2015&ndash;certified manufacturer and MBP-stocked supplier of both glass and plastic capillary tube formats. 
For specifications, size options, or bulk ordering support, <a href="https://mbpinc.net/contact-us" style="color: #236fa1; text-decoration: underline;">connect with the MBP team</a> to choose the right capillary solution for your laboratory application.

Flyer

51601-Group-Lab Supplies for Physicians Offices

Capillary Tube Accessories

Globe Scientific capillary tube accessories: sealing tray with Sigillum wax, 24-position, box/10 (51601); rubber aspiration bulbs individually (51674), 10/bag (51675), 100/cs (51676); plastic end caps 500/box (51672).

Manufacture

Bulb, for Capillary Tubes, EA

Bulb, for Capillary Tubes, BAG/10

Bulb, for Capillary Tubes, 10/Bag, 10 Bags/Unit, CS/100

Capillary Tube Holding Tray with Sigillum Wax Sealant, 24-Place, BOX/10

End Caps, for Capillary Tubes, BOX/500

51628-Lab Supplies for Physicians Offices

Capillary Tube, Microhematocrit, Borosilicate Glass, Precalibrated, 100/Vial, 10 Vials/Unit, BOX/1000

Globe Scientific 51628 — borosilicate glass microhematocrit capillary tubes, ammonium heparin–treated, precalibrated with a black 60 mm line. ID 0.55 mm, OD 1.55 mm, length 75 mm, 18 µL capacity. Box of 1,000 (100/vial × 10 vials). For packed cell volume (PCV) determination in clinical and veterinary hematology.

51680-Group-Lab Supplies for Physicians Offices

Plastic Micro-Hematocrit Capillary Tubes

Plastic Micro-Hematocrit Capillary Tubes by Globe Scientific — 75 mm PETG, 1.55 mm OD, 0.90 mm ID, 45 µL. Unbreakable plastic; spin 12,000 RPM for 4 minutes. 1,000 tubes per box. Available plain/blue tip (51680), ammonium heparinized/green tip (51684), and sodium heparinized/red tip (51686).

Capillary Tube, Microhematocrit, 100% PLASTIC, Blue Tip, Plain, 100/Vial, 10 Vials/Unit, BOX/1000

Capillary Tube, Microhematocrit, 100% PLASTIC, Green Tip, Ammonium Heparinized, 100/Vial, 10 Vials/Unit, BOX/1000

Capillary Tube, Microhematocrit, 100% PLASTIC, Red Tip, Sodium Heparinized, 100/Vial, 10 Vials/Unit, BOX/1000

51602-Group-Lab Supplies for Physicians Offices

Soda Lime Glass Micro-Hematocrit Capillary Tubes

Globe Scientific Soda Lime Glass Micro-Hematocrit Capillary Tubes are color-coded 75 mm tubes for PCV determination, supplied 100/vial, BOX/1000. Available as 51602 (blue tip, plain), 51608 (green tip, ammonium heparinized), and 51613 (red tip, sodium heparinized).

Capillary Tube, Microhematocrit, Soda Lime Glass, Blue Tip, Plain, 100/Vial, 10 Vials/Unit, BOX/1000

Capillary Tube, Microhematocrit, Soda Lime Glass, Green Tip, Ammonium Heparinized, 100/Vial, 10 Vials/Unit, BOX/1000

Capillary Tube, Microhematocrit, Soda Lime Glass, Red Tip, Sodium Heparinized, 100/Vial, 10 Vials/Unit, BOX/1000

Stirring Mixing Wire for Blood Gas Capillaries, 0.6mm x 9mm, Steel, 250/Vial, BOX/2500

51701 by MBP Inc: 0.6 mm × 9 mm steel mixing wires for magnetically agitating whole-blood in sealed heparinized blood gas capillary tubes before analysis. Supplied 250 wires/vial in a BOX/2500 (10 vials).

United States

Texas

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