Specimen Collection

Introduction

Proper sample collection and handling is an integral part of obtaining a valid and timely laboratory test result. Specimens must be obtained using proper phlebotomy techniques, collected in the proper container, correctly labeled (in the presence of the patient) and promptly transported to the laboratory. It is the policy of the laboratory to reject samples when there is failure to follow these guidelines. All specimens should be handled with universal precautions, as if they are hazardous and infectious.

Patient Preparation

Prior to each collection, review the appropriate test description, including the specimen type to be collected, the volume, the procedure, the collection materials, and the storage and handling instructions.

Specimen Collection Timing

The basal state (the early morning approximately 12 hours after the last ingestion of food) is recommended for determining the concentration of body constituents such as glucose, cholesterol, triglycerides, electrolytes, and proteins.

Blood composition is significantly altered after consuming food, and consequently alters many clinical chemistry tests. If a patient has eaten, and the physician still wants the test, then "non-fasting" is written on the request so the laboratory can make a notation on the report as to why some of the test values may be different than expected. For outpatients, provide the patient in advance with appropriate collection instructions and information on fasting, diet, and medication restrictions when necessary.

Specimens for Coagulation Testing

Specimens obtained for Coagulation testing must be collected and transported to the laboratory according to strict guidelines in order to assure accuracy of results. Refer to Coagulation Collection and Handling Guidelines for further instructions concerning requirements for Coagulation specimens.

Phlebotomy Protocol

  1. Knock before entering the patient's room.
  2. Introduce yourself
  3. Identify patient using two patient identifiers.
  4. Explain the procedure you will be performing.

Patient Identification

All patients from whom clinical specimens are obtained must be positively identified prior to specimen collection. Positive identification is the responsibility of the person collecting the sample.

Identify the patient prior to sample collection, using at least two patient identifiers. Verify the patient's name, unit history number on the identification armband (inpatients and ER), or drivers' license or other ID (outpatients) with the information on the requisition.

Precaution: Maintain awareness for sound-alike names and suffixes during patient identification. (i.e. Gonzalez and Gonzales; Sr. and Jr.)

Inpatients: Patients in the hospital should be wearing an identification bracelet that includes their last and first name, date of birth and a unique hospital number. Proper identification should include a three-way match using information on the ID bracelet and the test requisition, and the patient's stating of his or her name. If the patient does not have an ID bracelet, ask the nurse responsible for the patient to positively identify the patient and to place and ID bracelet on the patient. For unconscious or unidentified patients, it is important a unique number or identification system be used.

Outpatients: For an outpatient or ambulatory setting, there is no ID bracelet, but the patient should have been given identification labels when he/she registered. This label can be used along with asking the patient his/her name. If there is no label, then another means of identification should be used. Use at least two patient identifiers whenever taking blood samples.

DO NOT collect any specimen unless at least two positive identifications can be made.

Universal Precautions

All specimens should be regarded as potentially hazardous or infectious. Universal Blood and Body Fluid precautions should be observed.

Test Requests

The test requisition must include:

  • the patient's name
  • a unique identification number which assures positive patient identification (e.g., UH number)
  • the unit / clinic location
  • The name(s) and signature of the authorized provider requesting the test(s)
  • UTMB physician identification number if applicable
  • the test(s)/procedure(s) being ordered
  • the date and time of specimen collection is required on all requisitions
  • name or initials of person collecting specimen
  • pager/ phone number of appropriate contact person
  • office address of requesting physician if not part of the UTMB enterprise
  • diagnosis: ICD9 code or narrative description

Additional information may be required as necessary to comply with specific regulatory requirements or to meet clinical needs. These will be defined in divisional policies.

Specimen Identification and Labeling

All specimens submitted to Pathology Clinical Services for testing must be appropriately labeled to assure positive identification and optimum integrity of patient specimens from the time of collection until testing is completed and the result reported. In accordance with standards issued by the College of American Pathologists (CAP), American Association of Blood Banks, and The Joint Commission, all specimens must be labeled at the time of collection; in the presence of the patient, to maintain identity throughout the pre-analytical, analytical, and post-analytical processes. Refer to PCS Policy 7.01.03 Specimen Labeling Requirementfor additional requirements.

If there is a question as to the integrity and/or identification of a sample, the laboratory will reject the sample and request recollection. If extenuating circumstances exist that prevent recollection of the sample, and the physician or nurse requests that the test be performed on a sample that cannot be positively identified, the laboratory will analyze the sample with the following conditions:

  • The ordering nurse or physician must come to the laboratory to personally identify and relabel the request slip and patient sample.
  • The Inappropriate Sample Identification Release form must be completed and be legible. The correction must be dated and signed. Delegating this to another person will not suffice for medico-legal purposes.

Specimen Collection

Prioritize Collection:

"STAT" means special turnaround time and must be collected immediately. It may involve a patient whose medical condition has suddenly become very critical and must be treated as a medical emergency.

Fasting: Requests for "fasting" specimens are performed before routine requests, so patients can eat meals on schedule.

Order of Draw

Blood collection tubes must be drawn in a specific order to avoid cross-contamination of additives between tubes. The recommended order of draw for plastic vacutainer tubes is:

  1. First - blood culture bottle or tube (yellow or yellow-black top)
  2. Second - coagulation tube (light blue top). If just a routine coagulation assay is the only test ordered, then a single light blue top tube may be drawn. If there is a concern regarding contamination by tissue fluids or thromboplastins, then one may draw a non-additive tube (red top) first, and then the light blue top tube.
  3. Third - non-additive tube (red top)
  4. Last - additive tubes in this order:
  • SST (red-gray or gold top): Contains a gel separator and a clot activator.
  • Sodium heparin (dark green top)
  • PST (light green top): Contains lithium heparin anticoagulant and a gel separator.
  • EDTA (lavender top)
  • ACDA or ACDB (pale yellow top): Contains acid citrate dextrose.
  • Oxalate/fluoride (light gray top)

Note: Tubes with additives must be filled to their stated volumes and thoroughly mixed. Erroneous test results may be obtained when the tube is not filled to the stated volume and blood is not thoroughly mixed with the additive. Mix all tubes with anticoagulant by gentle inversion for 15 seconds.

(This is meant to be a guide and is not all-inclusive, if you have any questions, call the lab.)

Stopper Color (Plastic Tubes) Additive
1. Blood Culture Broth mixture
2. Light Blue * Sodium Citrate
3. Red None
4. SST (Red-Gray, or Gold stopper) Gel separator + clot activator
5. Dark Green Sodium Heparin
6. Light Green Lithium Heparin + gel separator
7. Lavender EDTA
8. Pale Yellow (ACDA or ACDB) Acid citrate dextrose
9. Light Gray Oxalate/fluoride
*Red Stopper color tube (no additive) should be used as "waste tube" if just a routine coagulation assay is the only test ordered or if there is a concern regarding contamination by tissue fluids or thromboplastins.
Reference: CLSI H3-A6 Procedures for the Collection of Diagnostic Blood Specimens by Venipuncture

Specimen Transport and Storage

All laboratory specimens shall be placed in leakproof containers (i.e., culturettes, vacuum tubes), then bagged in single, biohazard specimen bags. Place the requisition slip in the outside pocket of the biohazard specimen bag.

Tubed Specimens: Specimens may be sent through the tube system as follows:

  1. Place and seal the specimen in a biohazard bag, with the request slip in outside pocket.
  2. Place the biohazard bag into a Zip N' Fold pouch; completely sealing the pouch.
  3. Load the Zip N' Fold pouch into a pneumatic tube and send to the lab.

To ensure the validity of test results and the safety of laboratory personnel, specimens that leak in transit will be discarded, and the sender notified to resend another sample.

Spill Cleanup: If a pneumatic capsule is received that appears grossly wet or soiled, wear gloves before handling the capsule and removing the contents. Be aware that there may be broken glass or plastic inside! Remove sharp objects (broken glass or plastic) using forceps. Discard any wet or soiled padding as infectious waste. Clean the inside and outside surfaces of the pneumatic capsule with a hospital-grade disinfectant. Call the physical plant dispatcher and notify them of the contamination of the tube system.

Shipping: DOT and IATA requirements will be followed when shipping specimens for reference testing. Refer to PCS policy 3.18.16 - Packaging and Shipping of Infectious Substances and Diagnostic Samples for guidelines.

Reviewed 11/08/12 Anthony Okorodudu, PhD