Specimen collection and preparation

General Requirements

Questions related to specimen labeling or collection should be addressed to the appropriate laboratory supervisor.

Fasting Specimens:

An overnight fast is required for some tests. If applicable, the patient should not consume food or alcohol for 12 hours prior to specimen collection.

Specimen Type:

Serum (red-top tube, with or without serum separator):
Blood should be obtained aseptically by venipuncture in a manner routinely used for clinical testing. Allow blood to clot at room temperature for at least ten minutes, rim the clot with an applicator stick, if necessary, then centrifuge for at least ten minutes at 3000 rpm. Aspirate at least 2.0 mL of cell-free serum promptly to avoid hemolysis.

Venous blood (purple-top tube):
Blood should be at room temperature.

Urine:
Urine (preferably the first morning specimen) should be collected in a clean plastic container. Do not add preservative.

Joint Fluid:
Joint fluid should be collected in a red-top tube (without serum separator).

Cerebrospinal Fluid:
Cerebrospinal fluid should be collected in a clean, sterile tube. The specimen should not be blood tinged.

Cheek Swab sample (buccal cells):
Buccal cells should be collected using the materials and directions included in the Prenatal Cystic Fibrosis Screening kit. Patients should swab vigorously for at least 60 seconds.

Saliva:
After rinsing mouth with cold water, collect 2-3 mL of saliva in a clean container. Do not submit sputum or mouth washings.

Unless samples are shipped via local courier (for senders on FBR courier route), freeze samples and ship frozen via overnight shipper.

Labeling

The tube or container must be labeled with the patient's name, draw date, and the sender's identification.

Unacceptable Specimens

Some specimens are not adequate for testing due to improper collection or to degradation during transit. In these instances you will be notified of the problem. The list below includes rejection criteria for specific tests.

Alpha-fetoprotein Profile, Pregnancy (AEH) or Alpha-fetoprotein Profile Four (AFP4):
Whole blood samples which are more than 24 hours old or serum specimens which are more than seven days old will be rejected. In addition, grossly hemolyzed specimens will be rejected.

Antiphospholipid Antibodies (APA):
Specimens which are grossly hemolyzed will be rejected.

Cystic Fibrosis (CF):
Cheek swab samples received at FBR more than 14 days after sampling will be rejected.

Iron Status Profile (ISP):
Specimens which are visibly hemolyzed will be rejected.

Lupus-like Anticoagulant (LAC):
Whole blood is unacceptable; plasma must be separated. Hemolyzed plasma will be rejected. Specimens which are not received within 24 hours of collection will be rejected unless received frozen.

Special Handling Requirements for Specific Tests

Acetylcholinesterase, Amniotic Fluid (ACHE INH):
Amniotic fluid samples for AChE analysis should be carefully packaged to protect against extremes of temperature. Ship by overnight courier.

Alpha-fetoprotein Profile, Pregnancy (AEH) or AFP Profile 4 (AFP4):
Follow the instructions for serum collection. Ship samples at room temperature by overnight courier. Whole blood must arrive at FBR within 24 hours of collection.

Alpha-fetoprotein, Amniotic Fluid (AFAFP):
In the case of a bloody specimen, it is important that the amniotic fluid be centrifuged immediately. If possible, please send 1 mL of whole fluid and 2 mL of supernatant.

Cryoprotein (cryoglobulin/euglobulin)detection (CRYO):
This assay requires 4 mL of serum and plasma collected as follows:

Serum
Follow the instructions for serum collection except that the process of clotting, centrifugation, and separation of serum must be maintained at 37°C. Once the serum is separated, temperature is not as critical since nearly all cryoglobulins will dissolve once rewarmed to 37°C.

Plasma
Blood should be drawn as indicated above except using plasma rather than serum. Blood should be treated with citrate or oxalate, since fluoride or heparin may cause false positive results and EDTA will inhibit cryopricipitation of fibrin-fibrinogen complexes. If whole blood samples are to be sent to FBR, please call to confirm that we are able to perform separation immediately and that arrangements are made for the sample to be kept warm during transport.

Iron Status Profile (ISP):
Two mL of non-hemolyzed serum should be obtained following an overnight (12 hour) fast. Blood collection supplies should be free of iron contamination as exogenous sources of iron can interfere with the assay.

Lupus-like Anticoagulant (LAC):
Two mL of sodium citrated plasma is required. The plasma must be centrifuged and separated within 30 minutes of drawing and plasma received within 24 hours of collection, or the separated plasma may be frozen and shipped on dry ice.