Describe issues related to collection sample volume in pediatric patients.
Describe the optimal ages and usages for venipuncture versus capillary sampling.
List the proper order of multi-tube blood collection for venipuncture and for capillary collection.
Explain how mislabeled specimens might arise and how they might be handled in a pediatric laboratory.
Describe “add-on” samples and the factors which affect them.
Define issues that may arise in test validation in a pediatric laboratory.
The operation of a clinical laboratory requires a wide knowledge base and a considerable variety of skills. Expertise is necessary in: 1) operating, maintaining, and trouble-shooting a large array of instrumentation types ranging from particle counters and spectrophotometers to mass spectrometers and molecular diagnostics; 2) understanding chemical and immunological reactions and being able to trouble shoot and explain them to physicians; 3) handling of a variety of patient sample types and explaining acceptable versus unacceptable samples to other medical professional; and 4) being aware of the spectrum of tests available to medical professionals and appropriateness of test utilization patterns under different conditions.
A pediatric clinical laboratory adds another layer of complexity to the knowledge base requirements. Many of the regular day-to-day activities of operating a clinical laboratory are quite different between laboratories that provide services for pre-dominately adult populations and those whose patient base is primarily pediatric. Although the majority of the tests performed are the same or similar, many aspects of performing those tests must be tailored differently for the pediatric population and their unique needs. In addition, many pre-analytical aspects are quite different and specialized training and handling skills are required to understand these differences.
This chapter will deal with the pediatric-specific aspects of day-to-day laboratory operations.
BLOOD VOLUME AND VOLUME OF DRAW
The small total blood volume of infants and children limits the amount of blood that can safely be drawn from a pediatric patient. Current guidelines vary considerably between institutions, however most recommend that no more than 3% of total body volume be drawn per day, and 10% over 2 months in healthy children. Smaller amounts are recommended for ill and hospitalized children.1 Table 1-1 shows the calculated average total blood volumes and permissible collection volumes as a function of body weight and average blood volume.
TABLE 1-1MAXIMUM BLOOD COLLECTION VOLUMES (ML) FROM PATIENTS UNDER 100 LBS AS PERCENT OF AVERAGE TOTAL BLOOD VOLUME |Favorite Table|Download (.pdf) TABLE 1-1 MAXIMUM BLOOD COLLECTION VOLUMES (ML) FROM PATIENTS UNDER 100 LBS AS PERCENT OF AVERAGE TOTAL BLOOD VOLUME
|Weight ||Average Total Blood Volume ||Healthy Patients ||Hospitalized Patients |
|Collection (mL) ||Collection (mL) |
|Single ||Over 2 month ||Single ||Over 2 month |
|(lbs) ||(kg) ||(mL) ||3% ||10% ||2.5% ||5% |
|< 4 ||< 1.8 ||< 207 ||< 6 ||< 20 ||< 5 ||< 10 |
|4 – 6 ||1.8 – 2.7 ||220 ||7 ||22 ||6 ||11 |
|6 – 8 ||2.7 ...|