Collecting Samples for Clinical Testing

The following are general considerations for specimen collection, appropriate collection containers for specific testing and guidelines for sample submission.

For trace element, volatile compound analysis, forensic analysis and specimen types other than blood, serum, plasma or urine, read additional instructions.

Collecting Routine Clinical Specimens

Blood refers to whole blood drawn into evacuated tubes (e.g., Vacutainer® tube) containing anticoagulant. If the anticoagulant is not specified in the NMS Test Catalog, a lavender-topped, 7mL tube containing Na2EDTA is preferred.

Plasma should be obtained by drawing blood into an anticoagulant (preferably Na2 EDTA), evacuated tube. Invert tube at least eight times to mix, immediately centrifuge, and carefully transfer the supernatant plasma into a labeled plastic container (polyethylene vial).

Serum should be obtained by drawing blood into an evacuated tube containing no anticoagulant and with a non-coated interior. Allow 20 minutes for clotting. Immediately centrifuge and carefully transfer the supernatant serum into a labeled, plastic container (polyethylene vial).

Red Blood Cell Fractions should be prepared from whole blood using the procedure for plasma specimens. Transfer the plasma from the centrifuged red blood cell fraction and submit the red blood cells, labeling the specimen accordingly.

Urine specimens should be collected in a plastic (polyethylene) bottle. Do not fill bottle past the shoulder. Close with a screw cap, which has a self-sealing liner (e.g., 40 cc NMS-C bottle and cap).

Collecting Non-Routine Liquid Biological Specimens

While not all biological fluids are found in large volumes, make every effort to collect as much as possible. As a general rule, collect at least 4mL of each fluid. Place between 4 mL and 30 mL of fluid into a labeled screw-capped plastic container for shipping. It is not recommended to combine similar fluids from different sites, e.g., vitreous humor from each eye should be placed in separate collection containers.

Collecting Non-Routine Solid Biological Specimens

Stool: Collect an entire bowel movement and place into a clean, labeled 40 mL polyethylene bottle. Fill no more than 2/3 of the bottle. Write the total original weight on the label (mass or volume) of the specimen. Freeze. View frozen sample shipping instructions.

Meconium: Collect at least 5 grams, approximately 1 tablespoon, of the black-tarry Meconium sample and place into a clean 40 mL polyethylene bottle. The sample may be combined several times from each evacuation up to approximately 72 hours or when the sample starts to turn yellowish-green.

Hair: For metals testing only.

See individual metals tests for instructions in the NMS Labs online test catalog. 

Nails: Nail clippings may contain analytes of interest, which were deposited during the growth of the nail. Nail clippings (at least 0.5 g) from each finger or toe should be collected and packaged separately in acid washed plastic bottles. Each bottle should be labeled with the weight, if known, of the nail collected and its source, e.g., right index finger.

Collecting Samples for Metals Analyses

Specimens collected for trace-metals analyses must be protected from trace-metal contamination during collection. To reduce specimen contamination, use appropriate collection containers indicated below and wear powder-free gloves.

Blood, Plasma, or Red Blood Cells (RBC): Draw 7mL blood into a trace-metal free, EDTA Royal Blue Top Tube, unless otherwise indicated in the online test catalog specimen collection instructions.  Always check the online test catalog for the most up to date collection requirements.  

For RBC or Plasma samples, centrifuge blood as soon as possible after collection, and place plasma into a separate labeled, plastic, screw-capped, trace-metal free (EDTA) vial . Leave the RBCs in the original tube and replace stopper.

Serum: Draw 7mL blood into a trace-metal free, evacuated tube containing no anticoagulant (B/D No. 369737 Royal blue top Vacutainer® tube preferred). Always check the online test catalog for the most up to date collection requirements.  Other collection tubes, except the one indicated, contain a large enough volume of some metals to cause contamination of the sample as the needle punctures the stopper and blood is collected. Therefore, collect the trace-metal free vacutainers first when collecting multiple types of containers. Allow specimen to clot for at least twenty minutes. Centrifuge and transfer all of the serum into a labeled, plastic, screw-capped, trace-metal free (EDTA) vial.

Urine: Collect 20mL of urine directly into a labeled trace-metal free (acid-washed, deionized water-rinsed, air-dried), polyethylene bottle with a plastic lined screw cap or a trace-metal collection container supplied by NMS Labs. Call us to purchase your trace-metal collection container. Always check the online test catalog for the most up to date collection requirements.  

Collection of Specimens for Volatile Analysis

1. The original container that the sample was collected in should be sent intact to NMS Labs for analysis.
   Note: Serum Separator tubes are not suitable since the gel barrier often contains interfering substances.
2. DO NOT open the sample container between the time of collection and the time of analysis.
3. Do not transfer the sample to a secondary container, since this transfer may result in decreased concentrations of the volatile substance of interest, or potential contamination of the sample.
4. Fill the container as completely as possible to reduce the amount of airspace.
5. Store and ship all tubes and containers cold.

Contact NMS Labs Client Support at 866.522.2206 if you have questions about storage and shipping method for samples being submitted for volatile analysis.