Specimen Collection and Processing

In this chapter, we discusvs proper specimen collection techniques, processing, and storage of common sample types and the aspects of these activities that affect test values and their interpretation. 

Many errors can occur during the collection, processing, and transport of biological specimens. Minimizing these errors win result in more reliable information for use by healthcare professionals. Examples of biological specimens that are analyzed in clinical laboratories include whole blood serum plasma urine feces saliva spinal, synovial, amniotic, pleural, pericardial, and ascitic fluids and various types of solid tissue. The National Committee for CMnical Laboratory Standards (NCCLS) has published several procedures for collecting many of these specimens under standardized conditio ns.In addition, the NCCLS has published documents related to sample collection and analysis for specialized tests, such as sweat chloride (see also Chapter 27). 

Blood for analysis may be obtained from veins, arteries, or capillaries. Venous blood is usually the specimen of choice, and venipuncture is the method for obtaining this speci-men. In young children and for many point-of-care tests, skin puncture is frequently used to obtain what is mostly capillary blood arterial puncture is used mainly for blood gas analyses. 

In the clinical laboratory, venipuncture is defined as all of the steps involved in obtaining an appropriate identified blood specimen from a patient s vein.  

If appropriate the phlebotomist should verify that the patient is fasting. The patient should be comfortably seated or supine, if sitting is not feasible, and should have been in this position for 20 minutes before the specimen is drawn. This standardization minimizes differences in concentrations of blood constituents caused by variations in blood volume (hemoconcentration or hemodilution). Either of the patient s arms should be extended in a straight line from the shoulder to the wrist. An arm with an inserted intravenous line should be avoided, as should an arm with extensive scarring or a hematoma at the intended collection site. If a woman has had a mastectomy, arm veins on that side of the body should not be used because the surgery may have caused lymphostasis, affecting the blood composition. If a woman has had double mastectomies, blood should be drawn from the arm of the side on which the first procedure was done. If the surgery was done within 6 months on both sides, a vein on the back of the hand or at the ankle should be used. 

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Introduction to Principles of Laboratory Analyses and Safety Introduction to Principles of Laboratory Analyses and Safety Appendix Specimen Collection and Processing Preanalytical Variables and Biological Variation... 

University of Virginia, Department of Pathology Charlottesville, Virgmia Specimen Collection and Processing... 

Human specimens. In our laboratory, we first developed a good laboratory practice (GLP)-validated procedure for quantification of intact rafAON in control human plasma. The rafAON assay validation endpoints were standard curve, between-run precision and accuracy, within-run precision and accuracy, effects of dilution and freeze thaw, stability of rafAON at -80° C, and 4°C in plasma for various times, specificity, integrity of rafAON during plasma sample collection and processing, and lipid interference. The reader is referred to a previous citation for further details (17,27). 

The susceptibility of the assay to interfering substances must be determined. Exogenous interfering substances are introduced into the specimen, usually during specimen collection or processing. Common examples are heparin and phenol. Both inhibit amplification by polymerases. Endogenous interfering substances, such as bilirubin and fipids, can be increased by disease. 

Specimen acquisition and management Specimen collection, fixation, processing, sectioning Pathologist/technologist... 

The study was conducted at multiple Air Force installations. Dyess AFB, TX, served as the beta test site for participant selection, specimen collection, and exposure assessment. The lessons learned from the Dyess AFB beta test allowed the JP8 Research Team to improve data collection processes and study logistics, thus reducing the operational study impact at other Air Force bases involved in the study. Data was collected at the following sites Davis Monthan AFB, AZ, Seymour Johnson AFB, NC, Langley AFB, VA, Pope AFB, NC, Little Rock AFB, AR, and Hurlbert Field, FL. Specimens and data... 

In the following, sources of error that are important in the process of specimen collection and storage, as well as the physiological factors that cause error in the interpretation of the analysis of trace elements in human tissues are treated. 

Many types of specimens have been used to assess biological effects of aluminium serum and bone samples have provided the best clinical information. Collection and processing of specimens must be carried out in such a manner as to minimize contamination. 

Specimen reqnirements, including specimen collection, processing, storage, preservation, and the criteria for specimen rejection. 

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