Specimen collection is the first step in the process of acquiring quality results. Improper collection methods or techniques can result in erroneous results. Patients from whom clinical specimens are obtained must be positively identified prior to specimen collection. Follow your institution’s policies and procedures for the safe collection and handling of blood specimens for diagnostic testing.
NOTE: Blood of all patients are considered potentially infectious for hepatitis B virus (HBV) and other blood-borne pathogens, and universal precautions must be followed. Please refer to OSHA 1910.1030 - Bloodborne pathogens for more information.
To prevent the rejection of specimens, the following information must be legibly recorded on each irreversibly affixed label for specimens submitted to Stanford Health Care.
- Patient full first and last name
- Medical Record Number (or other unique identifier such as date of birth)
- Date and time of collection
- Initials or name of the person who identified the patient, collected, and labeled the specimen
NOTE: For Stanford Health Care or Stanford Children’s Health providers collecting specimens using EPIC, the date/time of collection and the collector identification may be electronically recorded.
After collection, mix the tubes by gentle inversion 8 to 10 times. Centrifuge at 3,000 – 3500 rpm for 10 to 15 minutes if indicated. Proper centrifugation is critical for proper separation of cells from serum or plasma. Store and transport specimen upright to maintain separation. Refer to the Test Directory webpages for specific collection and handling instructions for each test.
Some tests require plasma or serum to be separated and refrigerated or frozen within a defined time frame to preserve the integrity of the specimen. If a specimen is frozen for storage or for transport before arriving to the laboratory, do not allow it to thaw. Keep frozen on ice or dry ice as needed during transport. Store separated specimens upright in the refrigerator unless otherwise specified by the test requirements. Please refer to the Test Directory for specific information for specimen handling for each test.
- Avoid Hemolysis and stasis due to prolonged application of the tourniquet which can occur after 1 minute of application. When hemolysis occurs, red blood cells are lysed, and hemoglobin is released. When the serum is separated, the color will appear pink or red. Hemolysis can cause falsely increased results for many analytes, including potassium, magnesium, iron, lactate, phosphorous, ammonia, and total protein.
- Use a butterfly needle for pediatric patients and for patients for which venipuncture may be more difficult.
- Central lines. Avoid collecting specimens from veins where administration of fluids will cause abnormal levels of electrolytes, glucose, or drugs. Avoid contamination from heparin locks for coagulation tests.
- Use the correct tube and draw tubes in the proper sequence. Collect the specimen into the proper tube or container using the correct sequence of draw. This avoids cross contamination of anticoagulants in some tubes which can interfere with certain test results.
Order of Specimen Containers for Blood Draw
A. Obtain blood specimens in the following order:
- Blood Culture bottles
- Non- Additive tube (Red-top tube) (Plain)
- Coagulation tube (Light blue-top tube). A Light blue-top tube (Sodium citrate) tube is never the first tube drawn when using a butterfly. If a coagulation assay is the only test ordered, draw 1-2cc’s into a non-additive tube (red-top) first and then draw the Light blue-top tube.
- Red top tubes with clot activator
- SST Gold-top tube
- Last- Additive tubes in this order:
- Heparin: Green-top tube (Sodium heparin) or Gel- mint-top tube (Lithium heparin). Mint-top tubes must never be used to draw cytogenetics samples
- Lavender- top tube (EDTA)
- Gray-top-tube (Oxalate/fluoride)
- Other additive tubes
- Special instructions for collecting specimens for metal analysis apply. Please refer to the Test Directory for these tests.