The integrity of laboratory specimens and the test results depends upon proper patient preparation, specimen collection, labeling, handling, storage and transport. The test catalog provides specific information on container type, volume and special handling requirements for each test performed at the NPL production center and the most common tests out-sourced to our reference laboratory.
Follow all exposure control/Blood Borne pathogen guidelines adopted by your facility when collecting and handling laboratory specimens.
Specific test requirements are found in the alphabetical test listing in the Northern Plains Laboratory (NPL) test catalog. Please refer to the test catalog or feel free to call the NPL Call Center at 701-530-5700 with any questions.
For specimen collection tubes containing additives, the tube usually must be filled to its capacity to ensure the proper blood-anticoagulant ratio.
If multiple specimen types are being submitted for different types of testing, label the specimen transport tubes with the specific specimen type. For example, for a creatinine clearance indicate which sample is the serum and which sample is the urine.
Reference ranges for therapeutic drugs are often based on the time the specimens are drawn in relation to the time of the drug administration. If a drug level is available as either a peak or trough level, follow the specimen timing guidelines under the test dictionary. If submitting samples for both trough and peak levels, please remember to clearly mark the samples as to “peak” and “trough”.
An overnight fast of at least 8 hours is required for most fasting specimens. Some tests require a 12-14 hour fast. A specimen collected under different conditions must be designated non-fasting. If a test has specific fasting requirements, the requirements will be outlined in the test catalog.
Draw enough blood in the appropriate tube(s) to deliver sufficient serum/plasma volume, usually 2.5 times the amount of serum/plasma requested. Allow the tube to fill as per manufacturers directions. Tubes with anticoagulant need to be inverted as per manufacturer’s directions. Please note that most plastic serum tubes do have an additive to initiate the clotting cascade and therefore do require inverting to mix. Allow clotting at ambient temperature, unless otherwise specified in the individual specimen requirements. Centrifuge the specimen, following the manufacturers recommended spin time and speed, to separate the serum from red cells within 1 hour of collection or immediately for plasma separation. Rare testing may require different timing from collection to sample separation and will be noted in the test catalog.
For any tests that may be sent at room temperature or refrigerator temperature and collected on gel, the sample may be sent in the original collection tube provided a complete barrier is formed between the serum/plasma and red cells during centrifugation. For any tests that require freezing, plasma samples, or non-gel serum samples, transfer the serum/plasma to an appropriately labeled plastic transport tube without disturbing the red cell layer. Clearly identify the specimen as serum or plasma.
Draw sufficient blood in a specimen collection tube with the indicated anticoagulant for the test(s) ordered. Fill the tube to its vacuum capacity to ensure the proper blood-anticoagulant ratio. Invert the tube as per manufacturer’s directions to facilitate mixing and avoid clot formation. Transport the specimen in the original tube unless otherwise recommended. If for any reason, a portion of the sample has been removed from the tube prior to transport to NPL, this should be noted on the specimen and the requisition to eliminate sample cancellation due what would appear to be improper fill levels.
Specific requirements for obtaining platelet poor plasma are under the specific tests it applies to in the test catalog.
Transfer to plastic transport vial.
Sample collection directions are provided in the test catalog.
Transfer sample to plastic transport vial after thoroughly mixing the sample to ensure homogenous sample. For 24 hour urine samples, record the total volume on the sample transport tube.
See specific collection techniques under the appropriate culture in the test catalog.
The order of tube collection, when drawing either glass or plastic tubes, is formatted to avoid possible test result error due to cross contamination from tube additives.
NOTE: When dispensing blood from a syringe draw, all tubes must be in an upright position. The additives are generally at the bottom of the tube. Don’t invert the tube until the needle is extracted.
Royal Blue (Plain)
Blue (sodium citrate)
SST/Red gel/Gold (clot activator)
Gray (Potassium Oxalate Sodium Fluoride)
For all special coag testing (tests other than PT and aPTT), a discard tube is required. This discard tube must be a citrate tube.
Winged infusion set
When utilizing a winged infusion set for collection of a coagulation tube, a non-additive or a coagulation discard tube should be drawn first. The discard tube serves to fill the dead space in the collection tubing and assure the proper ration of anticoagulant to blood.
When performing specimen collection through a skin puncture, the lavender EDTA tube should be collected prior to the serum tubes to help prevent clots in the EDTA tube.
To assure positive identification and optimum patient specimen integrity, all specimens submitted to Northern Plains Laboratory must be labeled accurately and appropriately. As a general rule, two unique identifiers are required for proper specimen identification.
For clients with a High Volume Receiver (HVR), the label generated by the HVR must be placed on the transport tube.
If NPL determines that a label of any kind below the HVR label has a different patient name or demographic data, the first label on the tube will be considered the “correct” information.
For clients utilizing a manual requisition, clearly label the specimen with the first and last name and a control number label matching the requisition form.
A control number alone without a written name is not adequate identification.
Northern Plains Laboratory may refuse to accept specimens that are not appropriately labeled with 2 unique identifiers. In addition, we reserve the right to discard any unlabeled specimens. There are specific mandatory blood bank labeling requirements for those sites that NPL performs type and crossmatch testing. These requirements are available in the test catalog.
Specific specimen storage and transport temperatures can be found in the test catalog for each test.
The time taken for delivery of samples to NPL varies by each site and by courier. Please utilize the information in the test catalog to assure the sample will arrive without exceeding the specified time limits. In some cases, this requires anticipating longer time frames to arrive at NPL, such as during heavy postal service holiday.
We reserve the right to refuse specimens if they have been improperly collected, labeled or transported. The following represent some reasons for specimen rejection:
If recollection of the sample is impossible or would compromise patient care, it may be possible in some cases to report the result provided you are able to identify/verify that the specimen is the correct specimen. At NPL’s discretion, we may accept the specimen after a verification form is completed and a disclaimer statement is added to the result. In any case where specimen recollection is an option, this is the recommended avenue to ensure accurate results.
Manual test request forms are available through the NPL Call Center (701-530-5700).
Instructions for clients using High Volume Receiver (HVR)
The system should be kept at the main menu when not in use. Don’t leave the system in the log-in screen at the end of the day. Each a.m., the system should be rebooted.
Complete directions for ordering test through the HVR are available via hardcopy titled “HVR User’s Manual”.