What are the phases of laboratory testing and give the processes under this phase?

Variability may be introduced during phlebotomy: using the wrong specimen tube (e.g., wrong type and concentration of anticoagulant for specimen collection) and the effect of drawing blood from an infusion site.

Hemolysis can occur if the tubes with anticoagulant additives are not mixed gently 5-10 times; if blood is drawn from a hematoma; frothing of the sample; if the venipuncture site is not dry; with probing of the site; or traumatic venipuncture. Indwelling lines or catheters are a potential source of test error because most lines are flushed with a solution of heparin to reduce the risk of thrombosis.

Hemoconcentration from an increased concentration of larger molecules and formed elements in the blood may be due to several factors: prolonged tourniquet application (no more than 2 minutes), massaging, squeezing, or probing a site, long-term IV therapy, or sclerosed or occluded veins.

Prolonged tourniquet application will cause hemoconcentration of non-filterable elements (i.e. proteins). The hydrostatic pressure causes some water and filterable elements to leave the extracellular space. Significant increases can be found in total protein, aspartate aminotransferase (AST), total lipids, cholesterol, iron. This also affects packed cell volume and other cellular elements in whole blood.

Failure to draw the sample into the proper tube can interfere with test results by subjecting the sample to improper coagulation or to chemicals that alter the compounds to be measured. Failure to draw samples in the proper order of tubes may contaminate samples.

• Example: a specimen for a complete blood count should be drawn into a purple top tube, but drawing into a red top tube without anticoaculant will render the sample untestable.

Page 2

The "turnaround time" is defined as the reporting interval. The beginning time for this interval may be defined for various purposes as the time the test was ordered, the time the specimen was obtained, the time the specimen reached the laboratory, or the time the test was completed. For most routine testing, this is defined as the time from receipt of the specimen in the laboratory to the time the result is reported. Turnaround times are set by the need for timeliness of reporting for clinical decision-making.

A "critical value" is a test result that conveys life or death information and is defined for "out of range" test results that must be acted upon as soon as possible. For example, most laboratories define a serum glucose value below 40 mg/dL as a critical value, because that degree of hypoglycemia carries a high risk for morbidity and mortality. A critical value has life-threatening, time-dependent implications and must be directly reported to the health care provider for immediate action.

A "stat" test is defined as a quick turnaround time, generally an hour or less from specimen receipt until test result reporting. Such stat tests are usually ordered when the result is needed quickly for a decision regarding patient management. Such tests must be performed ahead of others in the queue. Many tests ordered from an emergency department, such as electrolytes, are handled as "stat" tests.

"Routine" test turnaround applies to specimens for patients without immediate need for results. This may be determined by the frequency the test is run in the laboratory: several times per day, once per day, once per week, etc. Tests results are availble within hours to days. For more esoteric tests sent out to a reference lab, results could take at least a week.

Page 3

These interferences tend to falsely increase the analyte value, but the interference effect varies by test methodology. Below, we will highlight hemolysis and cross-reactivity.

Hemolysis of red blood cells can release substances that alter or interfere with testing of analytes.

Example hemolysis releases potassium from red blood cells and leads to falsely high potassium values in serum or plasma.

Cross-reactivity can occur with serologic testing using antibodies.

Example about 1% of screening serologic tests for syphilis (STS) are false positives often in persons with autoimmune diseases with cross reacting autoantibodies.

Page 4

"Bedside" or "point-of-care" (POC) testing occurs in close proximity to the patient both in time and distance. For example, a finger-stick procedure can be done to obtain a drop of blood for use in a hand-held glucometer instrument to obtain a blood glucose test result for monitoring of control of diabetes mellitus. The patient may learn to perform this test (and likely performs it better than health care providers).

The specimens obtained and the instrumentation and the training of persons performing the POC test may not be as rigorously controlled as in a certified laboratory employing technicians who are professionals. However, the test results for POC situations may not require the degree of accuracy and precision of test results as specimens sent to the laboratory.

Governmental regulation of POC testing in the U.S. is based upon "CLIA" (Clinical Laboratory Improvement Amendments). In general, a proper laboratory (clinical laboratory) has obtained certification of its conformance to standards that help insure proper performance and reporting of tests. In general, "CLIA waived" tests are those that "(A) employ methodologies that are so simple and accurate as to render the likelihood of erroneous results by the user negligible, or (B) "the Secretary has determined pose no unreasonable risk of harm to the patient if performed incorrectly." (CFR�263a)

Problems that amplify POC testing error for the patient include: incoherent regulation, rapid availability of results, and immediate therapeutic implications.

A quality control methodology appropriate to the POC technology must be employed.

Page 5

Should tests be ordered singly or in bunches? In general, one should order the test needed to go with the clinical indication, such as troponin for an acute coronary syndrome. However, some tests need to be interpreted in context with similar tests, such as electrolytes.

Medicare tends to drive test reimbursement strategies. In 1998 Medicare defined panels or groupings of automated tests for which it will pay, and stated that if one of the tests in a panel is deemed to be medically necessary, then this can justify all the tests in the panel. A single diagnosis, or ICD-10-CM code (such as E10.65 Type 1 diabetes mellitus with hyperglycemia) will be sufficient for all the tests in a panel, even though some tests might not otherwise qualify. These standard panels are listed below (with CPT codes for illustration):

Basic metabolic panel (CPT 80048)

Comprehensive metabolic panel (CPT 80054) Albumin, Alkaline phosphatase, Aspartate aminotransferase [AST], Bilirubin, Calcium, Chloride, Creatinine, Glucose, Potassium, Protein, total, Sodium, and Urea nitrogen

Electrolyte panel (CPT 80051) Carbon dioxide [bicarbonate], Chloride, Potassium, Sodium

Hepatic function panel (CPT 80076) Alanine aminotransferase [ALT], Albumin, Alkaline phosphatase, Aspartate aminotransferase, ilirubin, total and direct, Protein, total, and Albumin

An individual practitioner could concoct a set of tests and define it as a "panel" but it would not necessarily be reimbursed, nor would such a panel necessarily be evidence-based. The purpose for restricting the number and use of panels is to diminish the amount of unnecessary testing performed.

Page 6

FDA approved tests done in a clinical laboratory have gone through a rigorous validation process for a specific purpose (a specified disease or condition). Medicare and other agencies or insurers may deem tests that have not undergone this process as "experimental" or without proven clinical utility, even though such tests may be widely used. For example, one may obtain a plasma TNF-alpha, but it is not FDA approved for any purpose and therefore deemed experimental and likely not to be reimbursed.

A Physician's Office Laboratory (POL) may not be subject to the rigorous licensing and inspection requirements as a regular hospital or commerical laboratory. However, the POL may only perform certain "CLIA" waived tests (Clinical Laboratory Improvement Amendments of 1988), typically those tests that serve a purpose for "point of care testing" (POCT) and are not complex to perform.

What is a "CLIA-waived" test? As currently defined in the regulation, waived tests are simple laboratory examinations and procedures that:

1. Are cleared by the Food and Drug Administration (FDA) for home use;

2. Employ methodologies that are so simple and accurate as to render the likelihood of erroneous results negligible; or

3. Pose no reasonable risk of harm to the patient if the test is performed incorrectly.

Provider-performed microscopy procedures may include moderately complex microscopy including vaginal wet mounts, cervical mucus, and urine microscopic examination. Complex testing, including cytopathology and tissue biopsy specimens, goes to an approved laboratory.