What blood tube colours are for which test?

Red: Serum chemistry tests, including hormone levels, and therapeutic drug monitoring. Light Blue: Coagulation tests, such as PT/INR and aPTT. Green: Plasma chemistry tests, including ammonia and lactate levels. Lavender: Complete blood count (CBC), haematology tests. Gray: Glucose and lactate testing.

Which Vacutainer tube is used for PT/INR, LFT, and FBS tests?

PT/INR testing requires a light blue Vacutainer tube (sodium citrate), LFT uses a yellow SST Vacutainer tube, and FBS is collected in a grey Vacutainer tube containing sodium fluoride.

What are vacutainer blood collection tubes colour codes?

Vacutainer blood collection tubes colour codes are used to indicate their intended purpose and type of additive they have. Based on the colour coding, health care professionals can recognise which vacutainer tube to use for which test.

What is vacutainer needle?

A vacutainer needle is a sterile, double-ended needle used for drawing blood. It connects to a vacutainer tube, allowing blood collection directly into the tube without exposure to air.

What is Rft vacutainer colour?

The RFT (Renal Function Test) typically uses a red or gold (SST) vacutainer tube. These tubes allow for serum collection, necessary for analysing kidney function markers like creatinine and urea.

What is blood vials colour coding?

Blood vials colour coding refers to the standardized colour system used on blood collection tubes to indicate their additives, test type, and handling requirements, ensuring accurate and reliable laboratory test results.

What is the SST tube color?

The SST (Serum Separator Tube) is usually gold or yellow in color. It contains a clot activator and gel separator, commonly used for biochemical, serology, and immunology blood tests.

What is the CBP test tube color?

The CBP (Complete Blood Picture) test is collected in a lavender or purple-top tube. This tube contains EDTA as an anticoagulant, which helps preserve blood cells for accurate analysis.

How to prevent blood from clotting in a test tube?

Blood clotting is prevented by using tubes that contain anticoagulants such as EDTA, heparin, or sodium citrate. Gently inverting the tube after collection helps mix the blood with the additive properly.

What is the difference between red and yellow vacutainer tubes?

Red tubes are primarily used for serum collection without gel separation, while yellow SST tubes contain gel and clot activator to improve serum separation after centrifugation.

How to use a vacutainer blood collection set?

A vacutainer set is used by inserting the needle into the vein, attaching the appropriate color-coded tube, and allowing vacuum pressure to draw blood automatically. After collection, the tube is gently inverted and safely removed for labeling and testing.

What is a vacutainer and why is it used in blood collection?

A vacutainer is a sealed, color-coded blood collection tube used to safely draw, store, and transport blood samples. The colors indicate the type of additive inside, ensuring accurate test results and proper sample handling.

What does the vacutainer color code mean?

The vacutainer color code indicates the type of additive in the tube and its intended use. For example, red is for serum tests, light blue for coagulation studies, lavender for CBC, and gray for glucose testing.

What is a grey tube blood test used for?

A grey tube contains potassium oxalate and sodium fluoride and is primarily used for glucose testing and blood alcohol levels. It preserves the blood sample by preventing glycolysis, ensuring accurate results.

Vacutainer Colour Coding Guide: Tube Colours, Additives & Test Uses

Blood collection tubes, known as vacutainer tubes, are not mere test tubes used for sample collection and storage. Depending on the type of test, different vacutainer tubes are used for blood sample collection. The functionality of each vacutainer tube is indicated by vacutainer colour coding: red-top tubes for blood bank testing, light blue for coagulation studies, Gray tubes for diabetes testing, Black for ESR, and so on.

The colour coding of vacutainers also indicates special handling instructions so that the sample is preserved for its intended purpose. Healthcare professionals in medical laboratories should be aware of vacutainer colour codes and their usage, as well as what additives they contain. This post will precisely teach them about vacutainer colour codes.

Vacutainer colour coding helps laboratory professionals identify the correct blood collection tube for specific diagnostic tests. Each tube contains a particular additive or anticoagulant that preserves the sample for accurate analysis. For example, CBC testing typically requires a lavender (purple) tube, PT/INR testing uses a light blue tube, while liver function tests are commonly collected in serum separator tubes (SST). Using the correct tube colour is essential to prevent sample contamination and ensure reliable test results.

What are Vacutainer Blood Test Tubes?

Vacutainer blood test tubes are sterile, sealed collection tubes used to draw and transport blood specimens for laboratory analysis. Each tube contains specific additives (anticoagulants, clot activators, or gel separators) designed to preserve the sample and enable accurate testing across a wide range of diagnostic needs.

Importance of Blood Collection Tube Colors

Color coding on blood collection tubes is essential for clinical accuracy and patient safety. The colored caps indicate the type of additive inside the tube, which determines how the blood sample is processed and which tests can be performed. Correct tube selection prevents sample rejection, reduces lab errors, and ensures faster turnaround times for results.

Significance of Color-Coded Tubes

Color‑coded tubes streamline the blood collection process for phlebotomists and laboratory staff by communicating tube function at a glance. This standardized system reduces misidentification, improves workflow in high‑volume settings, and supports compliance with global laboratory standards such as CLSI (Clinical and Laboratory Standards Institute).

Blood Collection Tube Colour Coding Table

Test	Recommended Tube Colour	Common Additive
CBC (Complete Blood Count)	Purple/Lavender	EDTA
ESR	Black Tube (Westergren Method)	Sodium Citrate
PT/INR	Light Blue	Sodium Citrate
LFT (Liver Function Test)	Yellow SST / Gold SST	Clot Activator + Gel
FBS (Fasting Blood Sugar)	Grey	Sodium Fluoride
RBS (Random Blood Sugar)	Grey	Sodium Fluoride
HbA1c	Purple/Lavender	EDTA
Serum Biochemistry	Red or Yellow SST	Clot Activator
Lipid Profile	Yellow SST	Clot Activator + Gel
Thyroid Profile	Yellow SST	Clot Activator + Gel

Understanding What Blood Tube Colors Are For Which Test

Each tube color corresponds to specific tests based on the additive it contains. For example:

Light Blue tubes are used for coagulation studies like PT/INR.

Lavender (Purple) tubes are typically used for complete blood counts (CBC).

Gold (SST) and Red are preferred for chemistry panels and serology.

This organized approach ensures that the collected sample remains stable and analyzable for its intended purpose

Vacutainer Colour Coding and Functionality

Colour Coding of Vacutainer	Additive	Common Uses
Red	No additive (sometimes a clot activator)	Serum chemistry tests, serology, blood bank testing
Gold (SST)	Serum separator tube with clot activator and gel	Serum chemistry tests, serology
Light Blue	Sodium citrate	Coagulation tests (e.g., PT, PTT, INR)
Green	Heparin (sodium or lithium)	Plasma chemistry tests, blood gas analysis
Lavender (Purple)	EDTA (Ethylenediaminetetraacetic acid)	Haematology tests (e.g., CBC, blood smears)
Gray	Potassium oxalate and sodium fluoride	Glucose testing, blood alcohol levels, lactate
Light Green (PST)	Plasma separator tube with lithium heparin and gel	Plasma chemistry tests
Yellow	ACD (Acid-citrate-dextrose) or SPS (Sodium polyanethol sulfonate)	Blood cultures (SPS), genetic and DNA testing (ACD)
Royal Blue	Trace element-free	Trace element testing (e.g., zinc, copper, lead), toxicology
Tan	EDTA	Lead testing
Pink	EDTA	Blood bank testing (e.g., crossmatching)
Black	Sodium citrate	Westergren sedimentation rate (ESR)
Orange	Thrombin-based clot activator	STAT serum chemistry tests (for rapid clotting)
White (PPT)	Plasma preparation tube with K2EDTA and gel	Molecular diagnostic tests (e.g., PCR)

Red

Red-top vacutainer tubes are among the most commonly used blood collection tubes in clinical settings. They usually collect whole blood specimens intended for serum separation. They can contain a clot activator, silica particles or a gel separator, which facilitate the clotting process– serum is separated from the cellular components of the blood.

Red vacutainer uses include chemistry panels, therapeutic drug monitoring, and hormone analyses also.

Red Vacutainer Uses

Red vacutainer tubes generally contain no anticoagulant or may contain a clot activator depending on the manufacturer. They are commonly used for:

Serum chemistry testing
Serology investigations
Immunology testing
Hormone analysis

These tubes allow blood to clot before serum separation.

Gold (SST)

The vacutainer colour coding of Gold-top for test tubes indicates their usage in efficient serum separation and sampling. These tubes contain a gel barrier that clearly separates the serum from the clot and cellular components upon centrifugation. It also prevents remixing of the serum and cellular components during transportation and handling.

SST tubes are useful in various clinical chemistry tests, including metabolic panels, liver function tests, and therapeutic drug monitoring. They are ubiquitous in settings where rapid serum separation and analysis are required.

Light Blue

The tubes contain sodium citrate. They are made for coagulation and clotting tests. Sodium citrate is an anticoagulant, which binds to calcium ions present in the blood to prevent the normal clotting process.

Which tube colour is used for PT/INR testing?

PT (Prothrombin Time) and INR (International Normalized Ratio) tests are collected in light blue vacutainer tubes containing sodium citrate anticoagulant. These tubes are specifically designed for coagulation studies and require accurate blood-to-additive ratios for reliable results.

Sodium citrate tubes are vital for accurate measurement. Doctors use them for prothrombin time (PT). They are also used for activated partial thromboplastin time (aPTT) and other coagulation tests. They aid in diagnosing bleeding disorders, liver diseases, and clotting issues. These tubes need centrifugation and plasma separation before conducting coagulation tests.

Green

Green-top colour coding of vacutainers indicates presence of the anticoagulant lithium heparin. It prevents blood clotting by binding to antithrombin III and enhancing its ability to inhibit clotting factors. Laboratories use lithium-heparin tubes in plasma chemistry panels. They also use them in drug monitoring and immunoassays.

Lavender (Purple)

Tubes containing the anticoagulant EDTA (ethylenediaminetetraacetic acid) with vacutainer colour coding of Lavender are primarily used for haematological tests and analyses. EDTA chelates calcium ions, preventing blood clotting and preserving cellular components.

What is the Purple Vacutainer used for?

Purple or lavender vacutainer tubes contain EDTA anticoagulant, which helps preserve blood cells for hematology testing. These tubes are primarily used for:

Complete Blood Count (CBC)
Hemoglobin testing
HbA1c analysis
Blood grouping procedures
Cell morphology examinations

When users search for "CBC tube color" or "CBC test vial colour," the correct answer is typically the purple or lavender EDTA tube.

They are also used in complete blood counts (CBC), white blood cell differentials, blood typing, and tests requiring whole blood or cellular analysis. EDTA also stabilises genetic material, making these tubes suitable for molecular diagnostics. However, inadequate mixing in Lavender tubes can lead to clotting or inaccurate cell counts, while over-mixing can cause hemolysis or cell damage. So proper mixing is paramount.

Gray

Gray-top blood collection tubes are used in glucose testing and monitoring. They contain sodium fluoride, which inhibits glycolysis, and potassium oxalate, an anticoagulant. Together, they preserve glucose levels in the blood sample for accurate measurements. When using tubes with Gray vacutainer colour coding, prompt mixing and processing is crucial to prevent glycolysis and obtain reliable glucose test results.

Light Green (PST)

Light green (PST) vacutainer tubes contain lithium heparin and a gel separator, used for plasma testing. They prevent blood clotting and quickly separate plasma from cells, making them ideal for chemistry tests. When handling PST tubes with vacutainer colour coding of Light Green, it is important to avoid shaking to prevent hemolysis and centrifuge promptly. Proper temperature conditions are also mandatory to preserve samples.

Yellow

Tubes with Yellow vacutainer colour coding contain acid citrate dextrose (ACD) as an anticoagulant, used for blood culture collection. They maintain sample integrity for microbiological analysis, so it is important to handle tubes gently to avoid contamination. They are inverted gently to mix the ACD with blood. Prompt transportation and storage at recommended temperatures are common prescriptions for yellow vacutainer tubes.

What does a Yellow Vacutainer contain?

A yellow vacutainer typically contains a clot activator and serum separator gel (SST). After centrifugation, the gel forms a barrier between serum and blood cells, helping preserve sample quality. Yellow tubes are commonly used for liver function tests (LFT), lipid profiles, thyroid testing, hormone assays, and routine biochemistry investigations.

In many laboratories, the yellow SST tube is among the most frequently used vacutainers because it supports a wide range of serum-based diagnostic tests.

Royal Blue

Royal blue vacutainer tubes are specialised blood collection tubes used primarily for trace element, toxicology, and nutritional studies. They are designed to prevent contamination of the sample, ensuring accurate results. These tubes typically contain either no additive (plain) or a clot activator for serum collection. The royal blue tubes are used for tests requiring metal-free blood samples.

Tan

Tan vacutainer tubes are specialised for lead testing. They can minimise contamination and ensure accurate lead level measurement in blood. The additive is EDTA working as an anticoagulant. Tan blood collection tubes are essential for environmental and occupational health assessments.

Pink

Pink vacutainer tubes are common in blood bank and transfusion services. These tubes contain EDTA (ethylenediaminetetraacetic acid) as an anticoagulant that preserves the sample for testing.

The vacutainer colour coding of Pink indicates that the tube is designed specifically for compatibility testing, cross-matching, and blood typing. Pink blood collection tubes facilitate safe blood transfusions by verifying donor-recipient compatibility and preventing adverse reactions.

Black

Black vacutainer tubes are used primarily for erythrocyte sedimentation rate (ESR) tests, which measure the rate at which red blood cells settle in a period of one hour. These tubes contain sodium citrate as an anticoagulant, maintaining the blood in a fluid state suitable for accurate ESR measurement.

The black vacutainer colour coding signifies their specific use for ESR testing, to diagnose and monitor inflammatory conditions, infections, and autoimmune diseases. Accurate ESR results help assess disease severity and treatment efficacy, where Black tubes play a crucial role.

Orange

Orange vacutainer tubes are used for rapid serum testing, typically in emergency situations. These tubes contain a thrombin-based clot activator, which accelerates the clotting process, allowing for quick serum separation. STAT (immediate) chemistry tests are time-sensitive, which is possible only with blood collection tubes with Orange vacutainer colour coding.

White (PPT)

White vacutainer tubes or plasma preparation tubes (PPT), are designed for molecular diagnostics and polymerase chain reaction (PCR) testing. The white stopper indicates their use for specialised testing, such as viral load and genetic testing.

ESR Blood Collection Tubes

ESR (Erythrocyte Sedimentation Rate) testing commonly uses a black-top tube containing sodium citrate when performed using the Westergren method. Laboratory protocols may vary, so healthcare professionals should always follow local testing guidelines and manufacturer recommendations.

Conclusion

Blood sampling is one of the crucial functions of medical and diagnostic laboratories. To serve the intended purpose, handling collection, storage and transportation have a significant role to play. In that connection, vacutainer colour coding is the centre of all these activities.