Today, laboratory testing is performed in many different settings, from the large reference lab that performs many complex tests to your own home, where you might take 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 or other body fluid specimen is sent “off to the lab” will help us to become more knowledgeable participants in our own healthcare.
All labs are not the same for the simple reason that not all tests are the same. Just as tests vary, labs also vary in complexity, the volume of tests performed, the technology utilized, and the number and type of professionals who perform the testing.
There are important differences among the various testing settings. This information will be useful in understanding the variety of laboratory tests that are available.
Almost all hospitals contain a laboratory, which is usually proportionate in size to the population it serves. Busy hospitals may process hundreds of samples in just one shift. Tests that are performed include those needed in emergency situations, such as markers for heart attack like troponin, tests where results are needed rapidly for patient care like stat testing, and other tests done in high volume, such as electrolytes. Hospital labs are generally used by all of hospital inpatients and by many outpatients who are being seen by hospital-affiliated physicians, such as at hospital-affiliated clinics and physician offices. However, 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 and 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 highly specialized tests using electron microscopy and immunohistochemistry, and still others can focus on surgical pathology, cytology, and autopsy, which are all associated with the analysis of cell and tissue structure. Some types of tests are sent to reference laboratories, which are more specialized, especially if the demand for them is low within the hospital.
Independent reference laboratory
Reference labs are usually private, commercial facilities that do high volume routine and specialty testing. Most of the tests performed are referred from physician’s offices, hospitals, and other healthcare facilities like nursing homes. While most hospitals try to do as many tests as possible in-house, reference labs are used for specialized tests that are ordered only occasionally or that require specialized equipment.
Since reference labs are some distance away, you may never step into a reference lab – unless you visit one of their phlebotomy 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.
Public health laboratory
Public health laboratories are run by state and local health departments to diagnose disease and protect the public from health threats, such as outbreaks of infectious diseases and environmental hazards. These labs perform tests to monitor, for example, the prevalence of certain diseases in the community, such as STDs; to investigate outbreaks of foodborne illness or water pollution; and to screen newborns for various genetic and metabolic conditions at birth. They also perform rare or unusual testing that clinical labs do not offer, like specialized molecular tests to characterize a unique strain of E. coli causing infection.
Public health laboratories are the go-to laboratories for first responders, such as in cases of bioterrorism like the 2001 anthrax attacks or natural disasters like Hurricane Sandy in 2012. In cooperation with the U.S. Centers for Disease Control and Prevention (CDC), Federal Bureau of Investigation (FBI), and other federal agencies, public health labs are part of the Laboratory Response Network (LRN). Many local clinical, federal, military, and international labs are part of the LRN in a partnership aimed at responding to biological and chemical terrorism and other public health emergencies in this country.
Laboratory tests may also be performed at the point of care (POC) – wherever you are receiving medical care, rather than in a distant laboratory. While results from clinical laboratories remain a crucial component of healthcare, they are now complimented by tests performed outside of the laboratory, wherever you are.
These point-of-care tests span many areas of medicine and are performed in a wide variety of locations: in your home, at the doctor’s office, in the emergency department, in an infectious disease containment unit, in ambulances, at an accident scene, in military clinics, in the radiology department, or on a cruise ship.
POC testing is growing as healthcare becomes more consumer-focused and individuals are interested in preventive care and managing chronic conditions. Technology has caught up to the demand for convenient, rapid tests results by enabling testing devices that are smaller, more portable, and easy to operate.
The most common point-of-care tests are blood glucose monitoring, home pregnancy tests, and blood chemistry tests. Other point-of-care tests that you may encounter include hemoglobin, fecal occult blood, rapid strep, and prothrombin time.
Tests included in POC programs must comply with quality standards comparable to tests performed in central laboratories (see Lab Oversight: A Building Block of Trust). Point-of-care testing will continue to grow as new devices become available, in part because they provide immediate information to you and your healthcare providers, allowing for more timely medical treatment.
To learn more, read the article Point-of-Care Testing.
Direct access testing (direct to consumer)
Direct access testing (DAT) allows consumers to order their own laboratory tests without consultation with their healthcare practitioner.
As with point-of-care (POC) testing, direct access testing, also called direct-to-consumer (DTC) testing or patient-authorized testing, has been growing in popularity over the past several years. DAT is another a reflection of Americans’ focus on health and preventive medicine, offering individuals the opportunity to take more active roles in their healthcare. Most states in the U.S. permit some degree of direct access testing.
In some respects, direct access testing has been around for some time. 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 individual’s request, without consultation with their healthcare provider. In some retail centers, people can walk into a lab and request certain tests; wellness centers offer health screens and other lab tests; and free-standing and mobile testing facilities such as those in grocery stores and pharmacies offer screening tests to the public.
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. More recently, genetic tests have become increasingly available through direct access as well.
As with POC testing and home testing, direct access testing may benefit individuals by reducing the expense of office visits, providing vital information to individuals who are concerned with a particular health problem or who may otherwise avoid testing due to inconvenience or concerns over privacy. However, most insurance companies do not cover tests that are not ordered by a health care practitioner, so you should expect to pay out-of-pocket for these services.
In addition, labs providing DAT services must provide consumers with reference ranges and some assistance in interpreting the results. However, you are not operating under the guidance of your healthcare provider, who may be better able to determine what tests you really need but also what the results of those tests mean in light of your specific clinical signs, symptoms, and medical history.
If you are having genetic tests performed, you may also consider meeting with a genetic counselor, who can help you to better understand these types of tests as well as how to interpret the results. To find out more about genetic counselors and to locate one, see the National Society of Genetic Counselors web site.
As individuals take on new responsibilities for their healthcare, laboratory testing is increasing in the home setting, one of the locations where point-of-care (POC) testing may take place. Some of the more common home tests include pregnancy tests and ovulation predictors, 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 (anticoagulant) medications. Other home tests allow individuals to collect samples at home that they then mail to a laboratory for analysis (for example, hepatitis C tests and some home HIV antibody tests).
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 health care practitioner.
Home tests offer 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 for performing the test were not followed.
All home tests must be approved by the U.S. Food and Drug Administration (FDA). Some companies sell unapproved home testing products; those may be unreliable, so be sure that the test kit you buy is FDA-approved. A list of over-the-counter in vitro diagnostic devices is available online from the FDA.
Home tests are considered screening tests, and it is important that you follow up with your health care practitioner in case you need additional laboratory testing and so you receive the highest quality care possible.