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What tube is sodium heparin in labcorp?

When collecting blood samples for testing at Labcorp, it’s important to use the proper tube type for each specific test. For tests requiring a sodium heparin tube, this anticoagulant additive prevents clotting so the sample can be used for certain blood chemistry analyses. Using the correct tube is essential to ensure accurate test results.

Sodium heparin tubes serve an important purpose in blood collection and medical testing. This tube contains the anticoagulant sodium heparin to prevent blood clots from forming in the collected sample. Clot activators are not present in sodium heparin tubes. The main uses of these tubes include:

  • Blood chemistry tests
  • Heparin level monitoring
  • Coagulation studies
  • Blood gas analyses

When collecting blood for Labcorp testing, each test has its own tube type requirement. For tests needing sodium heparin, it is essential to use the correct purple-top tube. This ensures the blood sample is viable for the required analyses. Using the wrong tube type can lead to inaccurate, rejected, or failed test results.

Sodium Heparin Tubes

Sodium heparin tubes contain the anticoagulant heparin sodium salt to prevent clotting of collected blood samples. Heparin works by binding to antithrombin III which inhibits thrombin and factor Xa in the clotting cascade. This prevents fibrin from being produced, stopping clot formation.

The key characteristics of sodium heparin blood collection tubes include:

  • Purple plastic tube top
  • Liquid sodium heparin additive
  • Anticoagulant concentration ~10-30 USP units sodium heparin per 1 mL blood
  • Typically a 5 mL draw volume tube
  • Available as serum separator tubes or non-gel tubes
  • Latex-free and silicone coated options

The purple top indicates the sodium heparin additive. The liquid state allows the anticoagulant to mix thoroughly with the blood once drawn into the tube. Heparin binds rapidly so coagulation is inhibited immediately. The tube contains enough heparin for accurate results even if the tube is not fully filled.

Using Sodium Heparin Tubes

When collecting blood samples for Labcorp testing, follow the proper protocol for using sodium heparin tubes:

  1. Verify with the lab test order that sodium heparin is the correct tube type.
  2. Check the tube expiration date and discard any expired tubes.
  3. Label the tube with the patient name, date/time of collection and any other identifiers required.
  4. Use the correct needle gauge for vein access.
  5. Draw the tube in the correct order if collecting multiple tubes.
  6. Fill the tube completely to ensure proper anticoagulant to blood ratio.
  7. Immediately after filling, gently invert the tube 8-10 times to mix the heparin.
  8. Follow the lab’s time limit and temperature instructions for sample storage/transport.

Proper collection technique is vital for accurate blood test results. Always use the correct tube type and additive for the ordered lab test.

Sodium Heparin Tube Tests

Sodium heparin tubes are primarily used for blood chemistry tests, including:

Test Type Details
Basic metabolic panel Measures sodium, potassium, chloride, CO2, glucose, BUN, creatinine, calcium
Liver function tests Measures liver enzymes, proteins, bilirubin
Lipid profile Measures cholesterol fractions, triglycerides
Cardiac marker tests Measures troponin, CK-MB for heart damage
Therapeutic drug monitoring Measures blood levels of medications

Sodium heparin tubes can also be used for:

  • Blood gas analysis – measures blood gases, electrolytes, and metabolites
  • Coagulation testing – PT, PTT, fibrinogen level
  • Flow cytometry immunophenotyping – identifies blood cell types

For genetic or molecular testing, sodium heparin tubes are sometimes indicated as they prevent DNA degradation. Always check the test requirements before collection.

Tube Additive Interactions

It’s important to avoid potential interactions between tube additives when collecting multiple tubes from one patient. Some key sodium heparin interactions to avoid include:

  • EDTA – EDTA chelates calcium which can affect some chemistry tests
  • Clot activators – Heparin can inhibit clot activator function
  • Glycolytic inhibitors – May reciprocally inhibit metabolite measurements
  • Citrate – Citrate acts as an anticoagulant and affects ionized calcium tests

Always check for prohibited tube combinations when collecting blood for multiple tests. Allow tubes to fill completely when drawing sequential tubes to prevent cross-contamination.

Special Handling

Sodium heparin blood samples require some special handling procedures after collection:

  • Gently invert 8-10 times – Ensures mixing of heparin immediately after collection.
  • Store upright – Prevents leakage and cross-contamination.
  • Maintain temperature – Store and transport as close as possible to patient body temperature.
  • Time limits – Observe lab time restrictions for delivery and analysis.
  • Avoid hemolysis – Hemolyzed blood has cell leakage which distorts results.

Failing to follow the proper collection, handling, and storage procedures can lead to erroneous or rejected sodium heparin blood test results.

Patient Preparation

To receive accurate test results, patients may need to follow special instructions to prepare for sodium heparin tube blood collection:

  • Fasting – For glucose and lipid tests, fasting for 8-12 hours may be required.
  • Medications – Taking medication may need to be avoided prior to therapeutic drug level testing.
  • Activity – Strenuous activity should be avoided right before some tests.
  • Time of day – Cortisol, testosterone, and other hormones follow circadian rhythms.

Let patients know in advance if they need to fast, restrict medications, or make other preparations before their lab test. This ensures the blood sample will reflect physiologic steady-state for accurate results.

Tube Selection Summary

Here is a summary of key points for sodium heparin tube selection and use for Labcorp testing:

  • Purple-top tube with liquid sodium heparin additive
  • Prevents blood clotting through heparin anticoagulant activity
  • Used primarily for blood chemistry analyses
  • Other applications include coagulation, blood gas, and flow cytometry tests
  • Requires specific collection, handling, and storage protocols
  • Avoid combining with incompatible tube additives from other tubes drawn sequentially

Verifying the correct tube type for lab tests is a crucial step for phlebotomists and healthcare workers. Following Labcorp guidelines for use of sodium heparin tubes provides quality blood specimens for accurate analysis results.


Sodium heparin blood collection tubes serve a vital role in modern medicine by providing quality blood samples for chemistry, hematology, coagulation, and other important lab tests. When collecting blood for Labcorp, meticulous attention to tube selection, additive interactions, handling, and processing ensures samples can provide the valid results caregivers need for optimal patient care. By using the proper purple-top sodium heparin tube for tests requiring this anticoagulant, phlebotomists and healthcare workers enable the medical lab to perform its lifesaving services.