Scheduling of a diagnostic test

This involves communication among the individual who prescribes the test, the patient, and the individual who performs the test. When diagnostic testing involves different departments, the nurse or unit coordinator may be involved with coordination of the scheduling of the tests so that the work is done in a timely way.

When multiple tests in various departments are prescribed, it is sometimes necessary to prioritize the test schedule because the method of conducting one test can interfere with the results of another. For example, x-ray studies that use contrast medium are performed before x-ray studies that use barium contrast material. Residual barium remains in the intestine for several days, and its opacity would obscure the view of the other tissues, such as the biliary tract and abdominal vasculature. Likewise, blood tests that use a radioimmunoassay method of analysis must be performed before or 7 days after a nuclear scan because the radioisotopes of the scan would interfere with the radioimmunoassay method of analysis of the blood and alter the test results. When these interfering factors involve tests performed by a single department, such as the laboratory, the priorities are routinely sorted out by the laboratory personnel.

Some priorities in scheduling are determined by the acuity of the patient. Particular test results may be needed rapidly for the assessment of the patient’s status, for correct medical diagnosis and treatment, or for evaluation of the patient’s response to treatment. Blood tests may be prescribed serially, for example, every hour for 4 hours; daily; or immediately (Stat). The nurse monitors to ensure that the tests are completed, as requested. The results are reported to the physician, as needed, and are posted manually or electronically in the patient’s record. When a test is needed urgently, the laboratory or diagnostic unit is notified, the scheduling arrangements are confirmed, and the test or procedure is completed immediately.

Some tests can be performed at the bedside with immediate results provided by point-of-care testing. Other tests, such as a culture, require time to obtain results and the results may not be available for several days or more. Nonroutine or special tests must be scheduled in advance. For example, positron emission tomography (PET) is a nuclear scan using a radioisotope that is made by splitting atoms in a cyclotron. This special and costly radioisotope is created on the day of the test, but has a short half-life of only 7.5 hours. When the person lives at home and is scheduled to come to the nuclear medicine department for the PET scan, it is essential that the scan starts on time. Prior to the day of the test, the radiology nurse phones the patient to review pretest instructions, answer any questions, and remind the person of the appointment.

Requisition forms

The laboratory requisition form is the major way to request the needed tests for the patient. The physician or health care provider who orders the test is also responsible to complete the requisition form. This simplified method avoids potential transcription errors that can occur when someone else completes the written request (McPherson & Pincus, 2007). Usually, the requisition is sent to the laboratory electronically, but it may be written manually.

The form must contain the same patient’s identifying information that is on the patient’s identification wristband and all hospital records. The information includes the patient’s name, identification number, birth date, gender, age, social security number (if possible), and physician’s name. Additional identifying data may be included, based on the institution’s preferences.

The needed tests are selected by the physician or health care provider. Specific information may be included, such as pertinent medical history, suspected diagnosis, date of last menstrual period, or pregnancy status. This additional information is used to help with diagnosis and to establish the correct reference values based on age, gender, or other biologic variables.

Once the data of the requisition form is entered into the laboratory information system, an individual bar code is created. This bar code is automatically printed on the labels for the collected specimens, along with the identifying patient information. The bar code is used to identify the specimen as it moves through laboratory analysis and also is a tracking device that ensures that all specimens are identified, analyzed, and the results are entered in the patient’s record.

Identification procedures

It is essential to perform a correct identification before collecting the specimen or starting a diagnostic procedure, such as bone marrow or other biopsy, culture, or any other specimen. The Joint Commission (2010) requires that the person who collects the specimen must obtain the patient’s identification from two different sources. One source is the name on the patient’s wristband and it is the same name as that on the requisition. The second source is that the patient states his or her full name. The patient’s room number or physical location cannot be used for identification purposes.

If the patient cannot respond, the staff nurse or a relative of the patient verifies the identity. There must be an exact match of identification among the two name identifications and the requisition information. The label also contains the same identifying information and after the specimen is obtained, the label is applied directly to the specimen container before leaving the patient.

Infection control: standard precautions

Standard precautions must be used when obtaining or handling a blood or body fluid specimen. Gloves must be worn during the collection procedure. If splashing or contact with a mucous membrane is anticipated, the nurse wears a mask, protective eyewear, and a gown or protective clothing in addition to the gloves.

All specimens of blood or body fluids are placed in the correct containers with tightly fitted lids to prevent leakage during transport of the specimen to the laboratory. After the completion of the procedure, the gloves and disposable clothing are removed and discarded. Hands are washed with soap and water.

Precautions are taken to prevent the puncture or cutting of one’s own skin with a contaminated needle, scalpel blade, or sharp instrument. To prevent needlestick injury, the needle-and-syringe unit is disposed of in a puncture-resistant container. The needle is not recapped, broken, bent, or removed from the syringe because of the risk of accidentally puncturing the hand.

Special reusable needles, such as those for a spinal tap or aspiration of a joint, are placed in puncture-resistant containers for transport to the area where they are cleansed and sterilized. Reusable instruments and diagnostic equipment are also cleansed and sterilized or disinfected according to established protocol.

The use of standard precautions is based on the premise that all patients are potentially infectious and that there is a risk of transmission of infection after exposure to blood or other body fluids. The precautions are used to protect all health care workers against blood-borne pathogens, including HIV.

Point-of-care testing

Point-of-care (POC) testing refers to methods of testing and analysis that bring the laboratory services nearer to the patient. This type of testing also is known as bedside testing, near-patient testing, or a rapid test. Satellite laboratories may be established near operating rooms, intensive care units, and emergency departments. Desktop analyzers may be used in these sites as well and in a clinic, an ambulatory care setting, a physician’s office, and long-term care facility. There is rapid turn-around time between obtaining the specimen and receiving the test results. Medical diagnosis and treatment is based on real-time values and will be more accurate, avoiding a long delay before the central laboratory results could be available. There has been a dramatic expansion of these rapid tests during the past decade and this trend is likely to continue in the future (Lewandrowski, 2009a; Nichols, 2007). A partial list of the point-of-care tests is presented in Box 1.

When electronic charting is used, the laboratory results are transferred electronically from the point-of-care analyzer to a central computer system and entered automatically in the patient’s record. If manual entry is used, the nurse must ensure that all the test results are charted in the correct order and time sequence.

With point-of-care methodology, reference values are different from the values of the same tests analyzed in the central laboratory. Different reagents, test equipment, and method of analysis create the differences in the reference values. The nurse refers to the point-of-care reference values provided by the central laboratory or the manufacturer of the point-of-care equipment for correct interpretation of the data.

Another category of point-of-care testing refers to the testing that is performed with small handheld instruments that analyze the patient’s blood in a few minutes. The specimen is obtained and the blood analyzed wherever the patient is located, including the home or the workplace. The patient is usually the person who performs the test as part of self-care responsibilities. Blood testing monitors are used for timely measurement of glucose levels in diabetics and more recently for monitoring the prothrombin time-international normalized ratio (INR) in those who are maintained on anticoagulant medication.

Expanded nursing role

Point-of-care testing involves an expanded role for nurses that overlaps with that of laboratory technicians. The nurse may collect the blood sample, perform the analysis, and produce the test results. When the patient monitors his or her own glucose levels or prothrombin-INR levels, patient teaching is an essential component of nursing care. The teaching begins in the hospital and continues by appointment in the specific clinic or office, until the patient can use the monitor, recalibrate the equipment accurately, interpret the results, and based on the results, adjust the medication according to the physician’s guidelines. Repetition of the teaching-learning activities continue until the patient can perform these functions with consistent accuracy.

The laboratory is responsible for point-of-care testing, policies, procedures, and maintenance of the equipment. Nurses, as the providers of direct patient care, may use the automated analyzers. Alternatively, multitasked nursing assistants may perform the point-of-care testing. As part of laboratory accreditation requirements, the person who uses this equipment must have formal training for each test, certification that the training has been completed satisfactorily, and an annual reevaluation of performance (Ehrmeyer & Laessig, 2009). Without the training there is a high incidence of inconsistent performance and inaccurate test results.

Transport of the specimen

The specimen is generally transported to the laboratory as quickly as possible. Some laboratory or pathology specimens become unstable shortly after they are collected. Specific factors, such as exposure to sunlight, warming, refrigeration, and exposure to air, can cause alteration or deterioration of particular specimens. For many blood tests, the unprocessed specimen will begin to deteriorate within a few hours. The phlebotomist and laboratory technician have responsibility for their own specimens. When needed, messengers may be used to deliver other specimens promptly, as from the operating room, emergency department, or patient care units.

When a fresh tissue sample must be analyzed for cytologic features, the specimen cannot be placed in fixative or preservative. Because the specimen will dry out after some exposure to the air, it may be delivered directly into the hands of the pathologist as soon as it is obtained. This coordination of activity provides immediate transport and tissue preparation so that the quality of the specimen is maintained.