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Blood Collection Tubes

Blood Collection Tubes

Blood collection tubes (often called vacutainer tubes) are sterile glass or plastic tubes pre-filled with a vacuum. When venipuncture is performed, the vacuum draws a precise volume of blood into the tube. Each tube has a color-coded cap indicating which additive (if any) is inside. These additives (anticoagulants, clot activators, separating gels, or preservatives) stabilize the blood for specific laboratory tests. For example, anticoagulants like EDTA, citrate, or heparin prevent clotting so that plasma or whole blood can be tested; clot activators (silica particles) induce clotting to yield serum; and gels (in “separator” tubes) form a barrier between cells and serum after centrifugation Some tubes also contain preservatives (e.g. sodium fluoride) that inhibit metabolic reactions (such as glycolysis) to stabilize analytes like glucose.

Types of Tubes (Color and Additive)

Common blood collection tubes (with their typical additives and uses) include:

  • Light Blue Top (Citrate): Contains 3.2% sodium citrate anticoagulant. Used for coagulation studies (e.g. prothrombin time PT and activated partial thromboplastin time aPTT). Citrate binds calcium to prevent clotting, producing plasma upon centrifugation. Because accurate testing requires a strictly 9:1 blood-to-citrate ratio, the tube must be filled to the marked line. After draw, immediately invert gently to mix.

  • Red Top (Plain/Serum): No anticoagulant (glass tube) or contains clot activator (plastic tube). Blood in a red-top tube clots naturally; after 10–60 minutes at room temperature the clot is removed by centrifugation to yield serum. Red tops are used for general chemistry and serology tests that require serum. (Note: For many chemistries, a “tiger-top” or Gold SST tube is preferred.)

  • Gold or “Tiger-Top” (SST – Serum Separator Tube): These have a clot activator plus an inert gel. The gel forms a barrier between clot and serum when centrifuged. They are colloquially called gold, marble-top, or tiger-top tubes. Use gold SST tubes for chemistry panels, immunoassays, and other tests on serum. After collection, invert 5–10 times to mix clot activator, allow clotting (≈30–60 min), then centrifuge. (CDC recommends waiting at least 30 min up to 60 min for complete clot formation.)

  • Green Top (Heparin): Coated with heparin (either sodium heparin or lithium heparin). Heparin inhibits thrombin, preventing clotting so that plasma is obtained. Green-top tubes are used for many STAT plasma chemistries (e.g. electrolytes, chemistry panels, blood gases). There is also a light-green/Lithium Heparin tube with a gel separator (PST) for plasma—used similarly in chemistry.

  • Lavender (or Purple) Top (EDTA): Contains K₂EDTA anticoagulant. EDTA chelates calcium and prevents clotting. Lavender top tubes yield whole blood or plasma and are the standard for hematology (e.g. CBC) and blood bank compatibility testing. Pink-top tubes are similar (K₂EDTA) and are typically used for transfusion crossmatch and other immunohematology tests.

  • Gray Top (Oxalate/Fluoride): Contains potassium oxalate (anticoagulant) and sodium fluoride (glycolysis inhibitor). Used for glucose and lactate measurements (fluoride stabilizes blood sugar by inhibiting enzymes) and for alcohol levels. After draw, invert to mix additives.

  • Yellow Top (ACD or SPS):

    • ACD (Acid-Citrate-Dextrose): Some yellow-top tubes contain ACD solution, used for specialized tests (e.g. HLA phenotyping, DNA/PBMC collection, autosomal genetic tests) because it preserves cells.
    • SPS (Sodium Polyanethol Sulfonate): Blood culture bottles (for microbiology) often have yellow or pink stoppers. These contain SPS, which prevents clotting and inhibits complement. (Don’t confuse these culture bottles with the serum/plasma tubes above.)

  • Other Colors: Specialty tubes include royal blue (trace element tubes, either EDTA or clot-activated, for lead/analyses), tan (lead EDTA), black (citrate for erythrocyte sedimentation rate), orange (rapid serum tubes with thrombin), and others. These are used only for specific tests. The exact coloring and additives are standardized (CLSI) but can vary slightly by manufacturer

Order of Draw

When multiple tubes are collected in one venipuncture, they must be filled in a prescribed sequence to avoid cross-contamination of additives. Tiny amounts of additive (or clot activator) can cling to the needle and contaminate subsequent tubes. The Clinical and Laboratory Standards Institute (CLSI) provides an “order of draw.” A common sequence is:

  1. Blood Culture Bottles (if required; yellow SPS).
  2. Light Blue (sodium citrate).
  3. Red or Gold (serum tubes).
  4. Green (or Light-Green) (heparin).
  5. Lavender (or Pink) (EDTA).
  6. Gray (fluoride/oxalate).

Any specialized tubes (e.g. royal blue for trace metals) are generally done last. Adhering to the order of draw helps ensure that test results are not biased by carryover of additives.

Collection and Handling

Blood is drawn using a double-ended Vacutainer needle and holder system. After venipuncture, the first tube is pushed onto the holder’s inner needle; the tube cap is punctured and its vacuum pulls blood into the tube. When the tube fills, it is removed and the next tube is inserted. Each tube’s vacuum stops drawing once its preset volume is reached.

Key handling steps:

  • Mixing: Immediately after filling, tubes containing anticoagulant must be gently inverted (usually 5–10 times) to mix blood with the additive. Overly vigorous shaking can cause hemolysis; under-mixing can allow small clots to form.
  • Clot formation: Serum tubes (red, gold) require time to clot before centrifugation (~30–60 min).
  • Labeling: Tubes should be labeled at the bedside with patient ID and collection time before leaving the patient to avoid misidentification.
  • Storage: After collection, tubes are transported to the lab (some tests require prompt processing or specific temperature).

All tubes are single-use and sterile. They bear manufacturer expiration dates: an expired tube may have lost its vacuum and will not fill properly. Always check expiry before use.

Pre-analytical Considerations

Proper tube selection and use are critical for valid results. Using the wrong tube (or wrong volume) can render a sample unusable. For example, filling a citrate tube below the required volume skews the citrate-to-blood ratio and invalidates coagulation tests. Contamination of tubes (e.g. wet needles, dirty stoppers) or reversal of draw order are common preanalytical errors. Following proper technique prevents additive carryover and avoids hemolysis or clot formation.

In summary, phlebotomists use color-coded evacuated tubes with specific additives to collect blood for lab tests. Selecting the correct tube (additive) and following the recommended draw order and mixing protocols (as per CLSI guidelines) ensures accurate laboratory results.

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Blood Collection Tubes

Blood collection tubes (often called vacutainer tubes) are sterile glass or plastic tubes pre-filled with a vacuum. When venipuncture is performed, the vacuum draws a precise volume of blood into the tube. Each tube has a color-coded cap indicating which additive (if any) is inside. These additives (anticoagulants, clot activators, separating gels, or preservatives) stabilize the blood for specific laboratory tests. For example, anticoagulants like EDTA, citrate, or heparin prevent clotting so that plasma or whole blood can be tested; clot activators (silica particles) induce clotting to yield serum; and gels (in “separator” tubes) form a barrier between cells and serum after centrifugation Some tubes also contain preservatives (e.g. sodium fluoride) that inhibit metabolic reactions (such as glycolysis) to stabilize analytes like glucose.

Types of Tubes (Color and Additive)

Common blood collection tubes (with their typical additives and uses) include:

  • Light Blue Top (Citrate): Contains 3.2% sodium citrate anticoagulant. Used for coagulation studies (e.g. prothrombin time PT and activated partial thromboplastin time aPTT). Citrate binds calcium to prevent clotting, producing plasma upon centrifugation. Because accurate testing requires a strictly 9:1 blood-to-citrate ratio, the tube must be filled to the marked line. After draw, immediately invert gently to mix.

  • Red Top (Plain/Serum): No anticoagulant (glass tube) or contains clot activator (plastic tube). Blood in a red-top tube clots naturally; after 10–60 minutes at room temperature the clot is removed by centrifugation to yield serum. Red tops are used for general chemistry and serology tests that require serum. (Note: For many chemistries, a “tiger-top” or Gold SST tube is preferred.)

  • Gold or “Tiger-Top” (SST – Serum Separator Tube): These have a clot activator plus an inert gel. The gel forms a barrier between clot and serum when centrifuged. They are colloquially called gold, marble-top, or tiger-top tubes. Use gold SST tubes for chemistry panels, immunoassays, and other tests on serum. After collection, invert 5–10 times to mix clot activator, allow clotting (≈30–60 min), then centrifuge. (CDC recommends waiting at least 30 min up to 60 min for complete clot formation.)

  • Green Top (Heparin): Coated with heparin (either sodium heparin or lithium heparin). Heparin inhibits thrombin, preventing clotting so that plasma is obtained. Green-top tubes are used for many STAT plasma chemistries (e.g. electrolytes, chemistry panels, blood gases). There is also a light-green/Lithium Heparin tube with a gel separator (PST) for plasma—used similarly in chemistry.

  • Lavender (or Purple) Top (EDTA): Contains K₂EDTA anticoagulant. EDTA chelates calcium and prevents clotting. Lavender top tubes yield whole blood or plasma and are the standard for hematology (e.g. CBC) and blood bank compatibility testing. Pink-top tubes are similar (K₂EDTA) and are typically used for transfusion crossmatch and other immunohematology tests.

  • Gray Top (Oxalate/Fluoride): Contains potassium oxalate (anticoagulant) and sodium fluoride (glycolysis inhibitor). Used for glucose and lactate measurements (fluoride stabilizes blood sugar by inhibiting enzymes) and for alcohol levels. After draw, invert to mix additives.

  • Yellow Top (ACD or SPS):

    • ACD (Acid-Citrate-Dextrose): Some yellow-top tubes contain ACD solution, used for specialized tests (e.g. HLA phenotyping, DNA/PBMC collection, autosomal genetic tests) because it preserves cells.
    • SPS (Sodium Polyanethol Sulfonate): Blood culture bottles (for microbiology) often have yellow or pink stoppers. These contain SPS, which prevents clotting and inhibits complement. (Don’t confuse these culture bottles with the serum/plasma tubes above.)

  • Other Colors: Specialty tubes include royal blue (trace element tubes, either EDTA or clot-activated, for lead/analyses), tan (lead EDTA), black (citrate for erythrocyte sedimentation rate), orange (rapid serum tubes with thrombin), and others. These are used only for specific tests. The exact coloring and additives are standardized (CLSI) but can vary slightly by manufacturer

Order of Draw

When multiple tubes are collected in one venipuncture, they must be filled in a prescribed sequence to avoid cross-contamination of additives. Tiny amounts of additive (or clot activator) can cling to the needle and contaminate subsequent tubes. The Clinical and Laboratory Standards Institute (CLSI) provides an “order of draw.” A common sequence is:

  1. Blood Culture Bottles (if required; yellow SPS).
  2. Light Blue (sodium citrate).
  3. Red or Gold (serum tubes).
  4. Green (or Light-Green) (heparin).
  5. Lavender (or Pink) (EDTA).
  6. Gray (fluoride/oxalate).

Any specialized tubes (e.g. royal blue for trace metals) are generally done last. Adhering to the order of draw helps ensure that test results are not biased by carryover of additives.

Collection and Handling

Blood is drawn using a double-ended Vacutainer needle and holder system. After venipuncture, the first tube is pushed onto the holder’s inner needle; the tube cap is punctured and its vacuum pulls blood into the tube. When the tube fills, it is removed and the next tube is inserted. Each tube’s vacuum stops drawing once its preset volume is reached.

Key handling steps:

  • Mixing: Immediately after filling, tubes containing anticoagulant must be gently inverted (usually 5–10 times) to mix blood with the additive. Overly vigorous shaking can cause hemolysis; under-mixing can allow small clots to form.
  • Clot formation: Serum tubes (red, gold) require time to clot before centrifugation (~30–60 min).
  • Labeling: Tubes should be labeled at the bedside with patient ID and collection time before leaving the patient to avoid misidentification.
  • Storage: After collection, tubes are transported to the lab (some tests require prompt processing or specific temperature).

All tubes are single-use and sterile. They bear manufacturer expiration dates: an expired tube may have lost its vacuum and will not fill properly. Always check expiry before use.

Pre-analytical Considerations

Proper tube selection and use are critical for valid results. Using the wrong tube (or wrong volume) can render a sample unusable. For example, filling a citrate tube below the required volume skews the citrate-to-blood ratio and invalidates coagulation tests. Contamination of tubes (e.g. wet needles, dirty stoppers) or reversal of draw order are common preanalytical errors. Following proper technique prevents additive carryover and avoids hemolysis or clot formation.

In summary, phlebotomists use color-coded evacuated tubes with specific additives to collect blood for lab tests. Selecting the correct tube (additive) and following the recommended draw order and mixing protocols (as per CLSI guidelines) ensures accurate laboratory results.

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  • Scope: Wholesale blood collection tubes and blood draw vials for hospitals, clinics, laboratories, EMS, medspas, dental practices, and institutional buyers across the US.
  • Primary use: Venipuncture and capillary specimen collection for serum, plasma, and whole blood laboratory testing — including routine panels, coagulation studies, blood bank procedures, and PRP preparation.
  • Tube formats covered: Standard adult vacuum tubes, microtainer tubes for low-volume and paediatric draws, and specialised plasma preparation tubes and blood bank hold tubes.
  • Key brands stocked: BD blood collection tubes (Vacutainer, Microtainer) and additional professional-grade options to support institutional formulary requirements.
  • Colour-coded system: All tubes follow the CLSI-aligned colour-coded stopper system — enabling fast, accurate tube identification at the point of collection.
  • Wholesale pricing: Competitive bulk pricing for licensed healthcare professionals; free US shipping on orders over $100; 5% off first purchase for new customers.
  • Serum Collection Tubes (SST): Gold and red-top tubes with clot activator and gel separator — primary tubes for CMP, thyroid panels, lipid panels, and most chemistry assays.
  • Anticoagulant Tubes — EDTA: Lavender and pink-top tubes for CBC, blood bank (type & screen), HbA1c, and haematology panels; pink tube blood draw variants designated for transfusion medicine.
  • Anticoagulant Tubes — Heparin: Lithium heparin tubes (green top) for plasma chemistry panels, including BMP and liver function tests; sodium heparin variants also available.
  • Coagulation Tubes: Blue-top sodium citrate tubes for PT/INR, aPTT, fibrinogen, and D-dimer — must be filled to the correct volume to maintain the 9:1 blood-to-anticoagulant ratio.
  • Specialised Tubes: CPT tubes for mononuclear cell isolation; plasma preparation tubes for PRP; blood bank hold tubes for cross-matching; grey-top fluoride tubes for glucose and lactate.
  • Paediatric & Capillary Tubes: Pediatric tubes for blood collection, including BD Microtainer formats for low-volume venous and capillary draws in neonatal and paediatric patients.
  • Lab Tubes — Broader Range: General laboratory tubes and lab test tubes supporting chemistry, microbiology, and molecular diagnostics workflows.
Tube Type Stopper Colour Additive Primary Tests Key Consideration
SST (Serum Separator) Gold / Red Clot activator + gel CMP, lipids, thyroid, hormones Allow 30 min clot time before centrifuge
EDTA Tube Lavender / Purple K2 or K3 EDTA CBC, HbA1c, haematology Mix 8–10 times; do not overfill
Coagulation Tube Blue 3.2% sodium citrate PT/INR, aPTT, fibrinogen Fill to line — underfill invalidates the result
Lithium Heparin Tube Green Lithium heparin BMP, LFTs, plasma chemistry Mix immediately; heparin inhibits PCR
Blood Bank Hold Tube (Pink) Pink K2 EDTA Type & screen, cross-match Two-ID labelling at bedside — AABB standard
Plasma Preparation Tube (PPT) Light Blue / Pearl Citrate + gel separator PRP, plasma isolation Preferred for aesthetic PRP procedures
CPT Tube Light blue (BD) Sodium citrate + Ficoll Mononuclear cell isolation Specialised centrifugation protocol required
Fluoride / Oxalate Tube Grey Sodium fluoride + potassium oxalate Glucose, lactate Glycolysis inhibitor — not for haematology
  • Hospital & clinic phlebotomy: Routine multi-tube draws for chemistry, haematology, coagulation, and blood bank panels using colour-coded collection tubes for phlebotomy following CLSI order of draw.
  • Laboratory analysis: Lab tubes and laboratory tubes supporting serum, plasma, and whole blood specimen processing for diagnostic assays across chemistry, immunology, and molecular panels.
  • Medspa & aesthetic medicine: Best blood collection tubes for PRP — plasma preparation and citrate-based tubes used by aesthetic professionals for platelet-rich plasma isolation in regenerative treatments.
  • Blood bank & transfusion medicine: Blood bank holds tubes (pink-top EDTA) for pre-transfusion testing, type and screen, and cross-matching in accordance with AABB standards.
  • EMS & emergency response: Field-use blood draw vials and anticoagulant tubes for point-of-care specimen collection by emergency medical professionals before hospital transfer.
  • Paediatric & neonatal care: Pediatric tubes for blood collection and microtainer tubes for low-volume capillary and venous draws in neonatal units and paediatric clinics.

This product is intended for use by qualified healthcare professionals or under the guidance of a licensed medical provider. It is not a substitute for professional medical advice, diagnosis, or treatment.

  • Match tube to test first: Confirm the required specimen type (serum, plasma, or whole blood) for each ordered panel before selecting a tube — refer to the tube-to-test table in the product guide above.
  • For CMP and routine chemistry: Select a gold-top SST (CMP tube) with clot activator and gel separator; allow adequate clotting time before centrifugation.
  • For coagulation studies (PT/INR): Use a coagulation tube (blue top, 3.2% sodium citrate) — always fill to the indicated line to maintain the correct blood-to-anticoagulant ratio.
  • For blood bank procedures: Use a blood bank hold tube (pink top) — apply two independent patient identifiers at the bedside immediately after collection per AABB requirements.
  • For PRP procedures: Select a plasma preparation tube rather than a standard EDTA or heparin tube — the gel separator and citrate anticoagulant are specifically designed for platelet-rich plasma isolation.
  • For paediatric or low-volume draws: Choose microtainer tubes or designated pediatric tubes for blood collection to minimise haemolysis risk and accommodate smaller specimen volumes.
  • For BD brand preference: BD blood collection tubes (Vacutainer and Microtainer lines) are available across all major tube types — specify BD when placing your order or contact our team for brand-matched bulk quotes.
  • Wholesale pricing: Blood collection tubes are available at competitive wholesale and bulk pricing for licensed healthcare providers, clinics, hospitals, laboratories, EMS agencies, and institutional buyers.
  • Blood collection tubes price: Pricing varies by tube type, brand, and order volume — contact sales@mountainside-medical.com or call +1 (888) 687-4334 for volume quotes and bulk order pricing.
  • Free US shipping: All orders over $100 qualify for free shipping across the contiguous United States.
  • New customer discount: First-time buyers receive 5% off their initial order — applicable to all blood collection tube orders.
  • Licensing requirements: Many tube types and associated products are intended for purchase by licensed healthcare professionals. Buyers may be required to provide proof of medical licensure or institutional credentials at checkout.
  • Bulk & institutional orders: High-volume procurement for hospitals, laboratory networks, or EMS departments — contact the sales team directly to discuss custom pricing, standing orders, and delivery schedules.
  • Contact: Email sales@mountainside-medical.com or call +1 (888) 687-4334 for order support, product availability, or bulk pricing enquiries.

The content on this page — including tube colour charts, order of draw guidance, additive-to-test matching information, and clinical application references — is provided for general professional reference purposes only. It is intended for use by qualified healthcare professionals, licensed phlebotomists, and certified laboratory personnel.

This content does not constitute medical advice, clinical protocol, or institutional laboratory policy. All tube selection decisions should be validated against your facility's current laboratory procedures, manufacturer product inserts, and applicable CLSI, AABB, or institutional guidelines in effect at the time of use.

Mountainside Medical Equipment is a wholesale supplier of medical supplies and equipment. Specific regulatory clearances, manufacturer certifications, and product-level compliance data: not specified in the provided data. Confirm product-specific regulatory standing directly with the relevant manufacturer prior to clinical use.

Products sold by Mountainside Medical Equipment are intended for use by or under the direction of a licensed medical professional. They are not intended for use by the general public and are not a substitute for professional medical advice, diagnosis, or treatment.

  • What is the correct order of draw for blood collection tubes?

    The CLSI-recommended order of draw (H3-A6) is: (1) blood culture bottles, (2) sodium citrate coagulation tubes (blue top), (3) serum tubes with or without clot activator and gel (red or gold top), (4) heparin tubes (green top), (5) EDTA tubes (lavender or pink top), (6) fluoride/oxalate tubes (grey top). Following this sequence prevents additive carryover between tubes, which can cause clinically significant interference with laboratory results.

  • What tube is used for a CMP (Comprehensive Metabolic Panel)?

    The CMP tube is a gold-top or red-top SST (serum separator tube) containing a clot activator and gel separator. Blood is allowed to clot for approximately 30 minutes before centrifugation, which separates serum from cells for chemistry analysis. The CMP tube is one of the most commonly drawn tubes in routine outpatient and inpatient laboratory panels.

  • What is a blood bank hold tube and when is it used?

    A blood bank hold tube is a pink-top EDTA tube designated for pre-transfusion testing procedures — including type and screen, ABO/Rh typing, antibody identification, and cross-matching. Per AABB standards, these tubes must be labelled with two independent patient identifiers at the bedside immediately after collection to prevent transfusion-related identification errors. A standard lavender-top EDTA tube is not an acceptable substitute in most blood bank protocols.

  • What is the difference between a lithium heparin tube and an EDTA tube?

    Both are anticoagulant tubes, but they serve different purposes. A lithium heparin tube (green top) inhibits thrombin and is used for plasma chemistry panels such as BMP and liver function tests. An EDTA tube (lavender or pink top) chelates calcium to prevent coagulation and is used for haematology panels including CBC and HbA1c. Heparin inhibits PCR-based molecular assays, so EDTA tubes must be used for molecular and blood bank testing.

  • What blood collection tubes are best for PRP procedures?

    For PRP (platelet-rich plasma) procedures, plasma preparation tubes (PPT) are the preferred choice. These tubes use a citrate-based anticoagulant and a gel separator that isolates the platelet-rich buffy coat layer during centrifugation. Standard EDTA or lithium heparin tubes are not equivalent substitutes — the anticoagulant type and gel formulation directly influence platelet concentration, activation state, and growth factor yield in the final PRP product.

  • What does the green top tube additive do?

    The green top tube contains either sodium heparin or lithium heparin as its additive. Heparin works by activating antithrombin III, which inhibits thrombin and several other clotting factors, preventing the specimen from clotting. This preserves the sample in its plasma state rather than allowing serum separation. Lithium heparin is the most common formulation because lithium does not interfere with electrolyte measurements the way sodium heparin would.

  • What is a microtainer tube and when should it be used?

    A microtainer tube is a small-volume collection tube designed for capillary blood collection (fingerstick or heelstick) or low-volume venous draws. BD Microtainer tubes are available in multiple additive formats — EDTA, lithium heparin, and serum — mirroring the full-size Vacutainer chemistry in a reduced volume. They are most commonly used in neonatal units, paediatric clinics, and point-of-care settings where standard-volume venipuncture is not appropriate.

  • Why does a blue tube blood test require the tube to be filled to the line?

    Blue top coagulation tubes contain 3.2% buffered sodium citrate and are formulated to achieve a precise 9:1 ratio of blood to anticoagulant. Underfilling the tube dilutes the specimen with excess anticoagulant, artificially prolonging PT and aPTT results. Overfilling reduces the anticoagulant concentration and can produce falsely shortened coagulation times. Correct fill volume is one of the most commonly cited sources of pre-analytical error in coagulation testing.

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