Each test has specific requirements for specimen collection. Be sure to review the specimen requirements for the requested test.

Note the following:

• Patient preparation instructions
• Proper specimen and amount to be collected
• Collection tubes and containers
• Handling, storage, and shipping requirements
  

Avoiding Common Errors in Specimen Collection

Careful attention to the specific requirements for each test specimen can help to avoid the following general specimen collection errors:

• Insufficient quantity
• Over filling tubes with specimen that requires freezing
• Hemolysis
• Failure to use the correct container for specimen collection
• Inaccurate and incomplete patient guidance
• Failure to label a specimen correctly and to provide all pertinent information
• Failure to tighten specimen container lids, resulting in leakage and/or contamination of specimen

Insufficient Quantity of Specimen

One of the most common and expensive errors in specimen collection is the submission of an insufficient sample for testing. Because of an insufficient sample, our laboratory has to send out a report marked QNS (Quantity Not Sufficient) and the patient has to be called back for a repeat collection at an additional expense and inconvenience to the patient and to the healthcare provider. To ensure an adequate amount of specimen, be sure to:

• Always draw whole blood in an amount 2.5 times the volume of serum or plasma required for a particular test (e.g., if 4 ml serum are required, draw at least 10 ml whole blood).
• For most serum and plasma tests, check to be certain that the transfer tube is at least half full.
• A specimen with a volume lower than the stated minimum volume for a particular test cannot be processed. Stated minimum volumes are absolute minimums which do not allow for retesting.
  

Reasons for a Rejected Specimen

• No Test Requisition Form (TRF)
• Spoiled specimen
• Test not marked on TRF
• Submitted wrong specimen for test requested
• No payment or billing information
• Quantity Not Sufficient (QNS)
• Total volume not recorded (see TRF)
• No Collection Date, inability to verify sample stability for test
  

Common Causes of Aberrant Test Values

Medications: Sometimes prescription and over-the-counter medications can interfere with chemical determinations or alter levels of the substances being tested. Medications with known or observed interferences are indicated in the individual description for tests affected.

Lipemia: Non-fasting blood specimens can have excessive amounts of lipids (fats), which can interfere with many test methods. If a specimen appears lipemic (milky), please determine if the patient is fasting. If the patient has forgotten to fast, it will be necessary to redraw the specimen when the patient is fasting. It is good practice to confirm the patient has fasted before drawing the sample. For patients with known hyperlipidemia, a longer fast than normal may be necessary. Normal fasting time required is 8 to 12 hours. Please note on the test requisition that the patient has a history of hyperlipidemia.

Hemolysis: Hemolysis occurs when red blood cells rupture and hemoglobin and other intracellular components spill into the serum. Hemolyzed serum may be pink or red rather than the normal clear straw color. For many of our tests, hemolysis requires redrawing the specimen. (Refer to specific test kit instructions.)