Quality Standards for Sample Collection in Coagulation Testing

Abstract

Preanalytical activities, especially those directly connected with blood sample collection and handling, are the most vulnerable steps throughout the testing process. The receipt of unsuitable samples is commonplace in laboratory practice and represents a serious problem, given the reliability of test results can be adversely compromised following analysis of these specimens. The basic criteria for an appropriate and safe venipuncture are nearly identical to those used for collecting blood for clinical chemistry and immunochemistry testing, and entail proper patient identification, use of the correct technique, as well as appropriate devices and needles. There are, however, some peculiar aspects, which are deemed to be particularly critical when collecting quality specimens for clot-based tests, and these require clearer recognition. These include prevention of prolonged venous stasis, collection of nonhemolyzed specimens, order of draw, and appropriate filling and mixing of the primary collection tubes. All of these important preanalytical issues are discussed in this article, and evidence-based suggestions as well as recommendations on how to obtain a high-quality sample for coagulation testing are also illustrated. We have also performed an investigation aimed to identify variation of test results due to underfilling of primary blood tubes, and have identified a clinically significant bias in test results when tubes are drawn at less than 89% of total fill for activated partial thromboplastin time, less than 78% for fibrinogen, and less than 67% for coagulation factor VIII, whereas prothrombin time and activated protein C resistance remain relatively reliable even in tubes drawn at 67% of the nominal volume.

Preanalytical quality improvement: in quality we trust

“…Commercial tubes have multiple components that contribute to the optimal separation of serum or plasma for laboratory analysis. For example, in glass blood collection tubes, the glass interior surface itself plays a key role in the activation of blood coagulation [28] . Recent use of plastic, as the principal material of collection tubes, has required the addition of silica particles or other clot activators for optimal formation of serum.…”

Harmonization in laboratory medicine: the complete picture

“…The most prevalent pre-analytical errors are those occurring during the collection of blood specimens; so the definition, implementation, and monitoring of suitable sample collection standards are highly conducive to improving the quality of the testing process [ 50 ]. In particular, harmonization projects should adhere to standardized protocols for patient preparation, time and use of appropriate devices and techniques for sample collection.…”

Quality Impact on Diagnostic Blood Specimen Collection Using a New Device to Relieve Venipuncture Pain

“…Presently in order to start a ''light-side'' period in the preanalytical phase and in patient safety, the attention of the laboratory professionals has been focused on some procedures previously regarded as consolidated, such as: (i) furniture changes among different manufacturers of syringes for blood gas analyses, which can represent new sources of laboratory variability; similar considerations apply to not validated vacuum tubes [28][29][30][31]; (ii) transport boxes unable to guarantee the maintenance of the temperature during blood specimens transportation [32]; (iii) traditionally accepted although incorrect paradigms ranging from the filling of vacuum tubes to the mixing procedures which appear unsupported by accurate experimental verification; e.g., recently it has been observed that there is no apparent need to mix all blood specimens after collection into vacuum tube systems by venipuncture [33,34]. On the other hand, apparently incorrect vigorous mixing of the primary blood vacuum tubes immediately after collection does not promote laboratory variability [35]; more so, no clinical impact has been observed in routine and specialized coagulation laboratory testing when the vacuum tubes are incompletely filled (when filled more than 90 % but \100 %) [36]. Obviously the ability of the phlebotomist to put the patient at ease is considered very important by outpatient [37].…”