What is a medical laboratory or lab?
A laboratory (Lab) is any facility that does laboratory testing on specimens derived from humans to give information for the diagnosis, prevention, treatment of disease or assessment of health.
What do medical labs do?
Medical laboratories perform the tests ordered by doctors to help diagnose, treat and monitor their patients. When your doctor orders a lab test, we collect a specimen – usually a small sample of blood, urine or other body fluid. We test the specimen and report the result to the doctor who ordered the tests.
What are medical lab tests?
Lab tests are examinations performed on blood, body fluids, tissues and other substances in order to determine what is normal or what is abnormal for you as a patient.
Why are medical lab tets performed?
It has been estimated that 60% to 70% of diagnoses and/or treatments are based on lab tests. Your doctor may request one or many lab tests depending on your condition. Your doctor uses lab results to identify changes in your health condition, diagnose a disease or condition, plan your treatment, evaluate your response to a treatment, or monitor the course of a disease over time.
Do I have to fast before my medical lab tests?
Fast means to not eat or drink anything for approximately 12 hours prior to the test. Fasting means you should not eat or drink any liquids except for water. You do not have to fast unless your doctor has ordered a “fasting” test. Two common tests that are generally done fasting are glucose and lipid panel.
Can I take my medications before I have medical lab tests?
Please ask your physician before having laboratory specimens collected.
When wil my test results be available?
Most test results are available within a week. Many test results are available within 4 to 24 hours. Multiple factors affect how soon test results are available. Tissue specimens, such as a tumor that is being analyzed for cancer, may take days to complete due to the numerous, complex steps that must be performed to process the specimen and requests for additional studies. Specimens submitted to be tested for bacteria or other microorganisms are cultured so the organisms can grow to a level where it can be seen. Routine cultures (e.g. strep throat or urinary tract infections) take a minimum of 24-48 hours to grow; other cultures (e.g tuberculosis) may take up to 21 days to grow. Many times, positive cultures require additional steps such as organism identification and susceptibility to antibiotics. Other specialized tests may be sent to an outside reference laboratory; this may lengthen the turnaround time.
What is a reference range?
Some tests provide a simple “yes” or “no” answer. Was the culture positive for strep throat? Did the test find antibodies to a virus that indicates an infection?
But for many more tests, the meaning of the results depends on their context. A typical lab report will provide your results followed by a reference range. For example, your results for a thyroid-stimulating hormone (TSH) test might look something like: 2.0 mlU/L, ref range 0.5 – 5.0 mlU/L . The test results indicates that it falls within the reference range.
How was that reference range established? The short answer is: by testing a large number of healthy people and observing what appears to be “normal” for them.
The first step in determining a given reference range is to define the population to which the reference range will apply, for example, healthy females between 20 and 30 years old. A large number of individuals from this category would be tested for specific laboratory test. The results would be averaged and range (plus or minus 2 standard deviations of the average) of normal values would be established.
The term “reference range” is preferred over “normal range” because the reference population can be clearly defined. Rather than implying that the test results are being compared with some ill-defined concept of “normal,” the reference range means the results are being considered in the most relevant context. When you examine test results from different populations, you quickly discover that what is “normal” for one group is not necessarily normal for another group. For example, pregnancy changes many aspects of the body’s chemistry, so pregnant women have their own set of reference ranges.
Effect of Age and Sex
For many tests, there is no single reference range that applies to everyone because the test performed may be affected by age and sex of the patients, as well many other considerations.
Some examples of variation in reference range based on age:
- Alkaline phosphatase is an enzyme found in the cells that make bone, so its concentration in the body rises in proportion to new bone cell production. In a child or adolescent, a high Alkaline phosphatase level is not only normal but desirable – the child should be growing healthy bones. But these same levels found in an adult are a sign of trouble – osteoporosis, metastatic bone disease (extra bone growth associated with tumors), or other conditions. It is because of these significant variations due to age that the few reference ranges that you may see on this site do not include ranges for children or adolescents. Experience from testing large numbers of people has led to different reference ranges by age group.
- Hemoglobin and hematocrit ( a red blood cell measure) both decline as a natural part of the aging process.
Examples of reference range variation based on sex:
- Creatinine is produced as a natural by-product of muscle activity and is removed from your bloodstream by your kidneys. Creatinine levels will be affected by person’s muscle mass as well as their kidney function. It is often measured as gauge of how well you kidneys are functioning. Because males have greater muscle mass than females, the reference range for males is higher than for females.
- Other factors Affecting Test Results
- Laboratories will generally report your test accompanied by a reference range keyed to your age and sex, it appropriate. Your physician then will still need to interpret the results based on personal knowledge of your health status, including any medications or herbal remedies you may be taking. A plethora of additional factors can affect your test results: your intake of caffeine, tobacco, alcohol and vitamin C; your diet (vegetarian vs. carnivorous); stress or anxiety; or a pregnancy. Even your posture when the sample is taken can affect some results, as can recent heavy exertion. For example, albumin and calcium levels may increase when shifting from lying down to an upright position.
All these considerations underscore the significance of taking blood or urine samples in standardized fashion for performing and interpreting laboratory tests (and home tests as well). It is important to comply with your doctor’s instructions in preparing for the test, such as coming, in first thing in the morning, before you eat anything, to get your blood drawn. That compliance makes your sample as close as possible to others; it keeps you within the parameters of your reference group.
What does it mean if my test result is out of the reference range?
First, there are few reasons why a test result could fall outside of the established reference range despite the fact that you are in good health:
- Statistical variability: Even when performing the same test on the same sample multiple times, 1 out of 20 (or 5%) determinations will fall outside an established range, based on the laws of probability. Sometimes, if the test is repeated on this same sample, the result will then be within range.
- Biological variability: If a doctor runs the same test on you on several different occasions, there’s a good chance that one result will fall outside a reference range even though you are in good health. For biological reasons, your values can vary from day to day. That is why a doctor may repeat a test on you and why he may look at results from prior times when you had the same test performed.
- Individual variability: Reference ranges are usually established by collecting results from a large population and determining from the data expected average (mean) result and expected differences from that average (standard deviation). There are individuals who are healthy but whose tests results, which are normal for them, do not always fall within the expected range of the overall population.
Thus a test value that falls outside of the established reference range supplied by the laboratory may mean nothing significant. Generally, this is the case when the test value is only slightly higher or lower than the reference range.
However, result outside the range may indicate a problem and warrant further investigation. Your doctor will evaluate your results in the context of your medical history, physical examination, and other relevant factors to determine whether a result that falls outside of the reference range means something significant for you. He may reorder the test. Perhaps the analyte being measured happened to be high that day due to one of the reasons stated previously or perhaps something went awry with the sample (the blood specimen was not refrigerated, or the serum was not separated from the red cells, or it was exposed to heat). Your doctor may also compare the latest test result to previous results if you have been tested for the same thong in the past to get a better idea of what is normal for you.
Laboratories will generally report the findings based on age and sex when appropriate and leave it to the physician to interpret the results based on factors such as diet, your level of activity, or medications you are taking. If you have a result that falls outside the reference range, talk to your doctor about what it means for you and what steps need to be taken next.
If you know of any special circumstances that could affect a test, mention then to your doctor, don’t assume your doctor has thought of every possible circumstance.
In general, reference ranges are specific to the laboratory that produces the test results. For many analyte, different laboratories use different kinds of equipment and different kinds of testing methods. This means that each laboratory must established its own reference ranges using data from its own equipment and methods. The laboratory must supply your test result with as accompanying reference range on the laboratory report. Consequently, there is no such thing as a standard reference range.
For a few other analytes, such as cholesterol and glucose, there has been a major effort to standardize the laboratory test methods and report formats. The result has been the establishment of a set of cut-off numbers that are different from reference ranges in that they reflect clinical decision points rather than a statistically “normal” range.
Remember, a reference range is merely a guide for your doctor. He or she will interpret the results in the context of you medical history and current presentation.
Hospital Infection Control Surveillance (Services)
Hospital acquired infections are a serious health hazard. It is important to minimize the risk of spread of infection to patients and staff in hospital. Good infection control practices reduce patient’s morbidity and mortality, length of hospital stay and cost associated with hospital stay.
Today all the health care providers are aware of the good infection control practices.
Synergy lab was the first to introduce infection control surveillance facilities in the region. These are carried out under the guidance of our Microbiologist who is actively involved in various Accreditations and Safe I programme for hospitals. We have received an excellent response from the leading hospital of the regions.
The infection control surveillance services include:
The high risk areas in various settings like
- 1.ICU (NICU, PICU, ICUs etc.
- 2.Operation theater
- 3.Dialysis Units
- 4.Burns Units
- 5.Transfusion Services Units
- 6.Food Handlers
- 7.Drinking Water
Both surface contamination and air quality should be investigated periodically (at least once a month) or more frequent if increase in infection rate from OTsICUs
Monitoring of device associated infections needs to be done on regular basis.
Central line tips with blood culture
ET tube secretions
Urine samples from catheterized patients
Water samples from humidifier
Sampling of drugs prepared for patients
Disinfection in dressing trolley
Surveillance clinical samples are sent to microbiology lab on basis of clinical data. An extensive reporting of the surveillance samples includes remedial measures and further actions needed.Transfusions Services Unit
Environment sampling: - Once a week
Blood component bags: - FFP and platelets
Active surveillance is suggested whenever clustering of positive cultures from cases are seen in the lab.
Screening of food handlers is recommended at 4 months. Samples include stool for ova, cyst and cultures for typhoid carriers.
Bacteriological surveillance from each source- Monthly
Air and Surface samples whenever required or requested. Our team provides education to the hospital/health care staff regarding Safe Infection Control Practices.
Many hospitals are availing the facility and we have excellent feedback from them as this has helped the hospitals to control HAI and reduce the antibiotic resistance rates.
Our microbiologist has formed Antibiotic Policy for many of our referring hospitals based on the sensitivity patterns of the growths in samples received from them. This has again greated helped out doctor clients in better patient care and in reducing antibiotic loads.