• Loading...

    Contact Us

    Laboratory Services Section
    MC 1947
    PO Box 149347 Austin, TX 78714-9347
    1100 W. 49th Street
    Austin, TX 78756-3199

    Phone: (512) 776-7318
    Fax: (512) 776-7294

    Phone Us Toll Free at:
    (888) 963-7111, ext. 7318

    Mailing/Shipping Info

    Email the Laboratory

STL Unsatisfactory Specimen Examples


 - STL Home | STL FormsUnsatisfactory Specimens | Sample Preparation -


All specimens received at the DSHS South Texas Laboratory (STL) are examined for quality and acceptability. Unsatisfactory specimens are rejected and no testing is performed. STL reports unsatisfactory specimen results to the submitting facility ONLY. It is the submitting facility’s responsibility to ensure than an adequate specimen is re-collected.

See below for correct sample preparation and information on, examples of, and tips for avoiding the most common unsatisfactory qualities reported by STL.

  • Correct Sample Preparation Example Photo
    Sample received in 6 ml Red Top - Spun down and poured off correctly.
  • Fibrin Clot Example Photo
    1. Spun down before proper clotting process- 15-30 minutes.
    2. Centrifuge either not set to correct RPM’s or not spun down long enough- 15-25 minutes.
    3. Arrive at STL will need to be poured off and respun.

  • Improperly Spun Down in Centrifuge Example Photo
    Results - Blood Cell Contamination Correction (Centrifuge RPM’s adequate):
    1. Be sure clotting process is complete; spin 15-30 minutes.
    2. Using anglehead centrifuge, turn samples ½ turn after first 15 minutes-spin 10 min. longer.

  • Complete Barrier Separation Example Photo
    Good separation with barrier showing complete seal of blood cells from serum. (Anglehead centrifuge)
  • Blood Cells Suspended in Sample Example Photo
    Arrived at STL with blood cells suspended in serum — either separated into transport tube or in original barrier tube. Cloudy but no Triglyceride content (swirls in sample denotes blood cells). STL will need to re-centrifuge sample. Some analytes may be affected. (Especially Glucose and Potassium.)
  • Blood Cells Suspended in Sample - with samples re-centrifuged Example Photo
    Re-centrifuged samples with “Gross Blood”- serum now clear and able to be processed through the Chemistry DXC 600 analyzer.
    1. #1 and #3 show slight hemolysis-May affect results of some analytes.
    2. If appear cloudy, check for Lipemia (Fat in blood) or suspended cells.
    3. Suspended cells will appear as swirling on shaking sample-Respin for 10 minutes- if still cloudy and no button in tube - probably Lipemia.

  • Three Types of Transfer Containers Example Photo
    1. 6 ml Red Top Tubes – Preferred (Labels attach directly to tube for analysis.)
    2. Other transfer vials are also acceptable. (BE SURE TO SEAL CAP TIGHTLY. Several samples received that have leaked into plastic bag causing contamination of the sample.)

  • Sample Volume – Quantity Not Sufficient Example Photo
    For best results:
    1. 0.5 ml - one time sampling – unable to verify questionable results.
    2. 1.0 ml - Preferable as “Minimum” Sample.
    3. 2.0 ml or more - Best for ability to give most accurate results. (Sample shows slight hemolysis)

  • Fill CBC purple top appropriately  Example photo
    Fill CBC to appropriate fill line located on side of purple top for proper EDTA dilution. Overfilled or underfilled tubes will be rejected.

  • Expired Tubes  Example photo
    Review expired tube stock, discarding any tubes that are expired. Specimens collected in expired tubes will be rejected.

  • Do not use syringes to transfer blood
    Do not use syringe to transfer blood; doing so will cause clotting.
    • Acceptable: Butterfly → Collection Tube
    • NOT acceptable: Butterfly → Syringe → Collection Tube
Contact Us

DSHS/South Texas Laboratory
1301 S. Rangerville Road
Harlingen, TX 78552
(956) 364-8748
(956) 412-8794

Aurora Martinez, M.T. (ASCP), B.S.
Laboratory Branch Manager

DSHS - MC1917
PO Box 149347
Austin, TX 78714-9347
Phone 512-458-7317
FAX 512-458-7588


Last updated September 24, 2015