Today, laboratory testing is performed in many different settings – from the large reference lab that performs complex kinds of tests to your own home, where you might do a pregnancy test or monitor your blood glucose levels.
Many of us, however, may wonder where our tests actually are performed. As we learn to take a more active role in our medical care, a clear understanding of what happens when our blood or urine specimens are sent “off to the lab” will help us to become knowledgeable more participants in our own health care.
All labs are not the same for the simple reason that not all tests are the same. Just as tests vary in complexity, and the technology required to perform them, so too do labs vary in their complexity, the volume of tests they can perform, the number and type of professionals who staff them, and the technology they have available.
The following descriptions explain some of the important differences among the various testing settings. We hope that they provide a useful addition to your understanding of laboratory testing.
At Home
More and more tests are being adapted for use at home, as patients take on new responsibilities for their health care. All home tests must be approved by the U.S. Food and Drug Administration (FDA). Some of the more common home tests include pregnancy tests and ovulation predictors for women, blood glucose monitors for diabetics, fecal occult blood tests to screen for colorectal cancer, and prothrombin time tests to monitor appropriate dosage of blood-thinning medications. There are other tests that allow patients to collect samples at home that they then mail to a particular laboratory for analysis (for example, home HIV antibody tests and hepatitis C tests); some of these may require a doctor’s order.
Home tests are available directly over-the-counter at pharmacies, over the Internet, by telephone, or by mail order. Some may require a prescription from a doctor. Home tests offer definite advantages, including convenience, privacy, and rapid results. However, consumers should be cautious when using home testing. For example, results can be inaccurate if the kit has not been stored properly, if the sample was not collected correctly, or if instructions were not followed. There are also companies selling unapproved home testing products, which may be unreliable – be sure that the test kit you buy is FDA-approved (a list of over-the-counter in vitro diagnostic devices is available at: http://www.fda.gov/cdrh/ode/otclist.html).
At the Point of Care
Laboratory tests may also be performed at the actual point of care (POC) – in other words, at the location of the patient rather than in a distant laboratory. Doctors’ offices and clinics are sometimes referred to as point-of-care sites. In hospitals, tests may be performed at the patient’s bedside.
Labs within physician offices and clinics are usually small in size, and medical assistants typically conduct the testing. You are likely to know and interact with the person taking your sample and conducting the tests in this setting. Laboratory tests at these locations are usually limited to uncomplicated tests.
Most physician and clinic labs conduct only a limited amount of testing due to the expense of equipment, supplies, and personnel for the office and the relatively small number of daily samples. However, they are convenient for patients and provide rapid results.
Point-of-care testing done directly at the patient’s bedside has been increasing thanks to technological advances that have brought about portable devices that are easy to use and produce immediate results. Examples include blood glucose tests, blood gas monitoring systems, and whole blood analyzers for cardiac markers and blood clotting tests. Tests included in POC programs must comply with standards just like those performed in central laboratories [see Lab Oversight article]. It is expected that POC testing will increase in frequency as new devices become available, in part because they may reduce delays and provide immediate information to physicians, allowing for more timely medical treatment.
In a Hospital Laboratory
Almost all hospitals contain a laboratory, which is usually proportionate in size to the population it serves. Tests that are performed include those needed in emergency situations (e.g., markers for heart attack such as CK, myoglobin, troponin) and those done in high enough volume to warrant acquisition of the necessary equipment. Hospital labs are generally used by all of the inpatients at the particular hospital and by many outpatients who are being seen by physicians with offices in the hospital. However, as a patient, you may never actually visit the hospital’s laboratory unless you are sent there for your sample collection.
Hospital labs may be segmented by type of testing, staffed by personnel trained in particular specialties. For example, there may be sections that focus on microbiology, hematology, chemistry, and blood banking. Other units may perform electron microscopy and immunohistochemistry tests, and still others can focus on surgical pathology, cytology, and autopsy. Some types of tests are sent to reference laboratories (see next page), which are more specialized, especially if the demand for them is low within the hospital.
At an Independent Clinical (“Reference”) Laboratory
Reference labs are usually private, commercial facilities that do high volume routine and specialty testing. Most of the tests they perform are referred to them from physician’s offices or hospitals. While most hospitals try to do as many tests as possible in-house if the volume is sufficient, reference labs are used for specialized tests that are ordered only occasionally or that require specialized equipment.
Since reference labs are usually distant from where patients receive their medical care, you may never step into a reference lab – unless you visit one of their drawing stations to have your blood drawn – although you probably have heard of them. Many employee health insurance plans require that you use a specific lab, which is often indicated on your insurance card.
Through a Direct Access Laboratory
As with home testing, direct access testing (DAT) has been growing in popularity over the past few years. Currently, 34 states permit health care consumers to order their own lab tests – without a medical order from their health care provider. Also known as patient authorized testing, DAT is another reflection of how health-conscious Americans have become and the opportunities available for them to take a more active role in their own health care.
In some respects, direct access testing has been around for a while. Over-the-counter home tests are a type of DAT since they do not require a prescription and can be bought and used at the consumer’s discretion. Now, the trend has expanded to include laboratories offering clinical tests at the patient’s request. In retail centers in Colorado, Montana, Missouri, Kansas, and Utah, patients can walk into a lab and request certain lab tests; wellness centers offer health screens and other lab tests; and free-standing and mobile testing facilities offer screening tests to the public, such as in grocery stores.
Most DAT labs limit the availability of tests to simple, general health tests such as complete blood counts (CBC), cholesterol levels, throat and urine cultures, diabetes screening (blood glucose tests), chemistry panels, PSA for prostate cancer, thyroid tests, HIV antibody tests, blood typing, pregnancy tests, and urine drug screens.
Theoretical or real advantages of direct access testing are that it may reduce costs for the patient by eliminating the expense of doctor’s office visits and can provide vital information to patients who are concerned with a particular health problem or who may otherwise avoid testing due to inconvenience or concerns over anonymity. However, most insurance companies do not cover tests requested and performed in this manner; therefore, you should expect to pay out-of-pocket for the lab’s services. In addition, while responsible labs will provide its consumers with reference ranges for the tests and some assistance in interpreting the results, you are not operating with the guidance of your physician, who may be able to better determine not only what tests you really need but is also more experienced in interpreting the results of those tests in light of your clinical signs, symptoms, and medical and family history.
Thursday, December 22, 2005
Point of Care Testing
Diagnostic testing performed at or near the site of patient care"
- Kost, GJ. Guidelines for point-of-care testing: improving patient outcomes. American Journal of Clinical Pathology 1995; 104 (Sup1):S111-S127.
A more restrictive definition as defined by CAP is "analytical patient testing activities provided within the institution, but performed outside the physical facilities of the clinical laboratories. It does not require permanent dedicated space, but instead includes kits and instruments, which are either hand carried or transported to the vicinity of the patient for immediate testing at that site”. Point-of-Care testing, or POCT, has a number of names. Ancillary testing, bedside testing, alternate site testing and decentralized testing all mean POCT.
- Kost, GJ. Guidelines for point-of-care testing: improving patient outcomes. American Journal of Clinical Pathology 1995; 104 (Sup1):S111-S127.
A more restrictive definition as defined by CAP is "analytical patient testing activities provided within the institution, but performed outside the physical facilities of the clinical laboratories. It does not require permanent dedicated space, but instead includes kits and instruments, which are either hand carried or transported to the vicinity of the patient for immediate testing at that site”. Point-of-Care testing, or POCT, has a number of names. Ancillary testing, bedside testing, alternate site testing and decentralized testing all mean POCT.
Point of Care Testing
Diagnostic testing performed at or near the site of patient care"
- Kost, GJ. Guidelines for point-of-care testing: improving patient outcomes. American Journal of Clinical Pathology 1995; 104 (Sup1):S111-S127.
A more restrictive definition as defined by CAP is "analytical patient testing activities provided within the institution, but performed outside the physical facilities of the clinical laboratories. It does not require permanent dedicated space, but instead includes kits and instruments, which are either hand carried or transported to the vicinity of the patient for immediate testing at that site”. Point-of-Care testing, or POCT, has a number of names. Ancillary testing, bedside testing, alternate site testing and decentralized testing all mean POCT.
- Kost, GJ. Guidelines for point-of-care testing: improving patient outcomes. American Journal of Clinical Pathology 1995; 104 (Sup1):S111-S127.
A more restrictive definition as defined by CAP is "analytical patient testing activities provided within the institution, but performed outside the physical facilities of the clinical laboratories. It does not require permanent dedicated space, but instead includes kits and instruments, which are either hand carried or transported to the vicinity of the patient for immediate testing at that site”. Point-of-Care testing, or POCT, has a number of names. Ancillary testing, bedside testing, alternate site testing and decentralized testing all mean POCT.
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