Diagnostic testing occurs in many different environments. Many test sites have shifted into community settings and away from hospitals and clinics.
Point-of-care testing (POCT) refers to medical testing done in close proximity to the site of patient care (e.g., in the primary care setting or acute care settings [emergency department, critical care units, ambulances]), thus moving toward decentralized testing. POCT is convenient for the patient, produces rapid reporting of test results, and allows for more timely assessment, management, and treatment.
Testing in the home care environment requires skill in procedures such as drawing blood samples, collecting specimens from retention catheters, proper labeling, handling, transporting of specimens, and documentation. Moreover, teaching the patient and family members how to collect specimens is an important part of the process.
In occupational environments, testing may be done to reduce or prevent known workplace hazards (e.g., exposure to lead) and to monitor identified health problems. This can include preemployment baseline screening, periodic monitoring of exposure to potentially hazardous workplace substances, and drug screening. Skill is required in drawing blood samples, performing breathing tests, monitoring and documenting specimen chain of custody, and obtaining properly signed and witnessed consent forms for drug, genetic, and HIV testing.
Nursing homes and long-term care facilities tend to produce more routine pretest, posttest, and follow-up testing because patients are frequently taken or transferred to hospitals for more complex procedures (e.g., computed tomography scans, endoscopies). Increasing numbers of full code (i.e., resuscitation) orders lead to greater numbers and varieties of tests. In addition, confused, combative, or uncooperative behaviors are seen more frequently in these settings. Understanding patient behaviors and using appropriate communication strategies and interventions for this patient population are necessary skills.
In the realm of public health, diagnostic test responsibilities focus on wellness screenings, preventive services, disease control, counseling, and treatment of individuals with problems. Case finding frequently occurs at health fairs, outreach centers, homeless shelters, municipal health departments, mobile health vans, and church settings. Responsibilities vary according to setting and may include providing test information, procuring specimens, and recommending referrals to appropriate caregivers. These responsibilities may even extend to transporting and preparing specimens for analysis or actually performing specimen analysis (e.g., stool tests for occult blood, tuberculosis [TB] skin testing, and procuring blood or saliva samples for HIV/AIDS testing).
The type of setting may also be determined by the type of test. Certain tests (e.g., cholesterol screening, blood glucose, electrocardiogram [ECG], lipid profiles, TB skin tests) can be done in the field, meaning that the service is brought to the patient’s environment. Other tests (e.g., x-rays using contrast media and those that require special patient preparation, invasive procedures, nuclear medicine procedures, hormone levels, and 24-hour urine testing panels) must be done in a healthcare setting. Magnetic resonance imaging and ultrasound procedures are commonly performed in freestanding or specialty diagnostic centers. Complex tests such as endoscopic retrograde cholangiopancreatography (ERCP), cardiac catheterization, and bronchoscopy may require hospital admission or at minimum outpatient status. As testing equipment becomes more technologically sophisticated and risks associated with testing are reduced, the environment in which diagnostic procedures take place will also shift.
Although patient populations and testing environments vary, the potential contagions are universal and of concern for both the patient and the healthcare provider. Standard precautions must be used in all testing environments to ensure safety for patients and healthcare providers. Refer to Appendix A for an in-depth discussion of standard precautions.