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• Step one: Perform an assay that detects either total or class specific antibodies (IgM or IgG) by ELISA/EIA or IFA. IgM usually peaks at 3-6 weeks after infection. IgG antibodies are detectable several weeks after infection and generally persist for years.

A negative result should not be a basis for excluding B as the cause of illness, especially if the specimen was collected within two weeks of symptom onset. If Lyme disease is strongly suspected, a second specimen should be collected 2-4 weeks after the first specimen. --A positive or equivocal result is presumptive evidence of the presence of anti-Bb, but should not be reported until second step testing is complete.

• Step two: Employs an assay that is more specific than first step assays. To date, Western blot assays have been used.

A negative result indicates no evidence of Bb infection at the time the specimen was collected. If Lyme disease is strongly suspected a second specimen should be tested.

A positive result provides evidence of past or current infection. Because the presence of specific antibodies does not always indicate current infection, a positive result cannot establish a diagnosis of Lyme disease.

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Description, Thyroid function studies are used to substantiate the presence or absence of hormone secretion abnormalities of the thyroid. These abnormalities may be either primary or secondary and are usually accompanied by clinically well defined signs and symptoms indicative of thyroid dysfunction.

Serum levels of thyroid hormones are useful to confirm clinical hyperfunction, hypofunction or euthyroidism of the thyroid gland. Thyroid function levels do not determine the etiology of thyroid disease.

In recent years, laboratory analysis to detect thyroid function has become more scientifically defined. Tests can be done with increased specificity, thereby reducing the number of tests needed to diagnose and follow treatment of most thyroid disease. The American Thyroid Association recommends the measurement of serum sensitive thyroid-stimulating hormone (TSH) levels complemented by an appropriate free thyroxine (FT4) estimate, as the best and most efficient combination of blood tests for diagnosis and followup of most patients with thyroid disorders. This is true for most ambulatory patients. These tests are not meant to be used for certain complex diagnostic problems or on an inpatient basis, where many circumstances can skew test results.

Indications: Thyroid function levels do not determine the etiology of thyroid disease but are necessary to define thyroid disease. Screening thyroid function tests are excluded from Medicare coverage by statutory exclusion.

Thyroid testing is used to:

- Distinguish between primary and secondary hypothyroidism;

- Confirm or rule out primary hypothyroidism;

- Monitor drug therapy in patients with primary hypothyroidism, and

- Confirm or rule out primary hyperthyroidism.

REASONS FOR NON-COVERAGE:

When no medical necessity has been demonstrated/documented.

When performed as a screening test which is statutorily excluded by Medicare.

Non-covered Diagnosis Codes: Submission of any diagnostic code not listed in the covered ICD-9 diagnosis section of model policy #96.18.

Only the test or combination of tests which best address the clinical signs and symptoms will be covered.

Following are examples of tests or possible combinations of tests which would be indicated for:

Hyperthyroidism: 84436 (T4); 84439 (Free T4)

Hypothyroidism: 84436 (T4) or; 84443 (TSH)

Thyroid binding abnormality: 88091 (thyroid panel including: T4 and T3) or; 80092 (thyroid panel including: T4 Total, and T3 and TSH)

Documentation Requirements: The ordering physician must provide documentation in the patient's clinical record that an evaluation of the patient's history and physical preceded the ordering of thyroid function tests and that delineates the clinical evidence of Thyroid disease to warrant the function testing.

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Anew testing service offered by McKennan Regional Laboratory utilizes an algorithmic technique to efficiently and cost-effectively evaluate abnormalities of coagulation, including lupus anticoagulant, abnormal bleeding, prolonged clotting times, family history of bleeding disorders, and thrombosis.

In order to facilitate the investigation of these patients, MRL offers several different coagulation consultations. With a brief patient history and related clinical information (i.e., medications, blood products, etc.) a panel of screening tests is performed. Based on the history and the initial laboratory results additional testing may be indicated. The results and interpretation are provided in a written report by the pathologist.

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LUPUS ANTICOAGULANT

includes: PT, PTT, dRVVT(dilute Russell's Viper Venom) , Interpretation.

PROLONGED CLOTTING TIME

A. The ova and parasite exam has traditionally been ordered when evaluating patients with diarrhea. Other than Giardia lamblia, intestinal parasites are extremely rare in the patient population of this area. For example, since the institution of Giardia antigen testing at McKennan Hospital Laboratory in Jan. of 1993, no intestinal parasites other than Giardia lamblia have been identified in patients that did not meet the O&P criteria. Giardia antigen testing is highly sensitive and specific. For most patients being evaluated for diarrhea, Giardia antigen testing is the most cost-effective test. In patients who are recent immigrants, have traveled outside the U.S. or for which there is other reason to suspect a parasite other than Giardia lamblia, the ova and parasite exam may be appropriate.

Note: Giardia antigen testing is performed at St. Luke's-Midland Hosp., Queen of Peace Hosp., and McKennan Hospital Lab. Our thanks to Jib Cerrito of the McKennan Microbiology department for the background information on Giardia antigen testing.

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NEW INSTRUMENTATION ON-LINE AT ST. LUKE'S MIDLAND RMC.
St. Luke's Midland RMC has recently changed over to the Mannheim Boehringer Hitachi 912 chemistry analyzer. This is a computerized, programmable, discrete, fully automated chemistry analyzer. It is capable of performing potentiometric and photometric assays of a wide range of analytes. One of the main features of the Hitachi 912 is that it is computerized. The computer triggers and monitors automatic calibrations, evaluates 0.C., tracks reagent stability, evaluates patient results and controls robotics. The 912 also features fully automated operation. Once the analyzer has been placed in the operate mode, the instrument processes samples until all programmed samples have been completely assayed and printed. No further operator interaction with the analyzer is required except to evaluate and report results.

St. Luke's Midland RMC lab has also gone live with the Becton Dickinson Bactec 9240 blood culture instrument. This new system eliminates the need to specify if an ARD (antimicrobial removal device) is needed because any Bactec blood culture bottle will routinely remove antimicrobials. With this new system in place, cultures need to be inoculated directly into the blood culture bottles. The SPS transport bottles used previously can no longer be used.

The Avera health system labs are in the process of implementing like instrumentation to assist in cost containment and charge standardization throughout the system. Currently St. Luke's Midland RMC lab and Queen of Peace lab are using the Hitachi analyzer. McKennan and Sacred Heart labs will go live with their Hitachis later this summer. Other instrumentation will be standardized as instrumentation is updated.

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Queen of Peace Hospital laboratory began performing Troponin I testing on May 15. Troponins are very specific for diagnosing myocardial damage. Levels are elevated within 3-4 hours, peak at 12-16 hours and remain elevated for 5-9 days. Troponin I's are run on a STAT basis. Serum is the specimen of choice. Sample volume is 220 ul. On-instrument turnaround time is approximately 15 minutes.