Frequently Asked Questions

SECTION I: FUNDAMENTAL PTH ANALYTES & TESTS

1. What do the terms "CAP" and "CIP" represent?
2. How is CIP (7-84 PTH) different from CAP" (1-84 PTH)?
3. Why is the relative proportion of 1-84 PTH (or CAP and its inhibitor 7-84 PTH (or CIP) important?
4. How is CAP/CIP ratio value determined?
5. How many tests are needed to calculate the CAP/CIP ratio?
6. What does the current "intact" PTH test measure?
7. Why does the SCL "intact" PTH value now always come out lower than the Nichols "intact" PTH assay value?
8. What makes the Scantibodies CAP Assay unique?
9. Can I use the Nichols-intact and Bio-Intact PTH assays to generate the same CAP/CIP Scantibodies ratio?
10. Is the CAP/CIP ratio available from other laboratories?
11. How many replicates does SCL run for each Total Intact PTH and CAP assay?
12. What makes the SCL 2nd generation Total Intact PTH test unique?


SECTION II: INTERPRETATION OF PTH TEST RESULTS

1. How is the "intact" PTH assay value interpreted?
2. How should the CAP (1-84 PTH) and CAP/CIP (1-84/7-84 PTH) values be interpreted?
3. How can the CAP/CIP ratio assist in making therapeutic decisions (i.e.. dosing of vitamin D, surgery, etc.)?
4. How often should the CAP values and the CAP/CIP Ratio be measured?
5. What CAP/CIP ratio can be considered pathological?
6. How can there be an abnormal CAP/CIP ratio when the PTH level is normal?
7. How soon after a change is made in calcium or vitamin D dosing should PTH values change?
8. What happens to the CAP/CIP ratio when the dose of vitamin D or calcium is decreased?
9. How should the CAP/CIP ratio be considered in prescribing parathyroidectomy?
10. What is a dynamic low bone turnover disease and why has it been increasing over the years?
11. What is the gold standard and how do you determine which PTH test is best for determining bone status in the ESRD patient?
12. Why are there so few studies that correlate PTH tests to bone biopsies?
13. What does it mean if a patient has troublesome high values in the "intact" PTH assay that cannot be suppressed with vitamin D?
14. Is this new PTH test only for renal bone disease?
15. What is the evidence for calcification?
16. Does an over-administration of vitamin D pose a risk of calcification?
17. How could the "intact" PTH assay results mislead and result in the over-administration of vitamin D?
18. Is calcification reversible?
19. Is calcification life threatening?
20. How soon does vascular calcification begin for the dialysis patient?
21. Has anyone else (other than Dr. Malluche) confirmed the correlation of the 1-84/7-84 PTH ratio with bone histology?


SECTION III: PROCESSING THE PTH BLOOD SAMPLES

1. What is wrong with shipping whole blood as a sample to a central laboratory for PTH testing?
2. What is an FDA-approved PTH kit package insert?
3. Who is responsible for making decisions regarding the medical necessity for and type of patients testing?
4. What is the correct specimen to draw for the CAP/CIP ratio?
5. What needs to happen to the blood sample after it is drawn for the CAP/CIP ratio?


SECTION IV: BILLNG FOR PTH TESTS

1. Does the CAP/CIP ratio represent double billing?
2. Is the same CPT code used for both the "intact" PTH test and the CAP test?
3. Does Medicare reimburse for "intact" PTH and CAP tests and the CAP/CIP ratio?
4. Does the Total Intact PTH test and CAP Assay cost more than the old "intact" PTH test?
5. Who does the billing for the SCL Total Intact PTH and CAP tests for Medicare patients?
6. Is SCL an accredited laboratory


SECTION V: OTHER PTH TESTS

1. Has any other biochemical test been demonstrated to be superior to the CAP/CIP ratio for predicting renal bone disease?
2. Are assays from other companies for CAP (1-84 PTH) and the CAP/CIP ratio all the same?
3. Why doesnt SCL enable other laboratories to actually perform these new PTH tests?


SECTION VI: QuantiFERON®-TB GOLD TEST

1. Why QuantiFERON®-TB Gold (QFT-Gold) versus tuberculin skin test (TST)?
2. How does it work?
3. What is the difference between active and laten TB?
4. When should you use the QuantiFERON®-TB Gold (QFT-Gold)?


Section I

FUNDAMENTAL PTH ANALYTES AND TESTS

1. What do the terms "CAP™" and "CIP™" represent?

"CAP™" stands for Cyclase Activating PTH and is 1-84 PTH. "CIP™" stands for Cyclase Inactive PTH and is most likely the fragment 7-84 PTH. The fact that CIP™ (7-84 PTH) does not activate adenylate cyclase is suggested by additional published evidence that CIP™ (7-84 PTH) may operate through a PTH C-terminal receptor (that may not activate adenylate cyclase); whereas, CAP™ 1-84 PTH operates through the classical PTH/PTHrp receptor that does signal through adenylate cyclase.

2. How is CIP™ (7-84 PTH) different from CAP™ (1-84 PTH)?

As listed above, structurally, "CAP™" is 1-84 PTH and "CIP™" is most likely 7-84 PTH. Both CAP™ (1-84 PTH) and CIP™ (7-84 PTH) are secreted by the parathyroid gland. Functionally, CIP™ (7-84 PTH) causes the body to do the opposite of 1-84 PTH or CAP™, in terms of serum calcium, osteoclast formation, bone resorption, bone turnover, and bone formation. CIP™ (7-84 PTH) has an inverse biological activity compared to that of 1-84 PTH.

(ref. Slatopolsky et. al., Kidney International 2000; Vol.58:753-761. Divietti et. al., Endocrinology 2002; 143(1):171-176. Nguyen-Yamamoto et. al., Endocrinology 2001; 142(4);1386-1392. Faugere, et. al., "The Effects of PTH-(1-84) on Bone Turnover are Antagonized by PTH-(7-84) in Thyroparathyroidectomized and Nephrectomized Rats." J Am Soc Nephrol 12:2001, 764A, presented at the ASN Annual Meeting, 2001.)

3. Why is the relative proportion of 1-84 PTH (or CAP™) and its inhibitor 7-84 PTH (or CIP™) important?

If CAP™ (1-84 PTH) is proportionately much greater than CIP™ (7-84 PTH), then the patient is in a high bone turnover state. If CIP™ (7-84 PTH) is greater proportionally than CAP™ (1-84 PTH), (i.e., the CAP™/CIP™ ratio is less than one), then the untreated renal dialysis patient is in an adynamic low bone turnover state.

(Ref. Monier-Faugere, Malluche, et. al., Kidney International, 2001; 60:1460-1468.)

Bone biopsy studies have demonstrated that the CAP™/CIP™ ratio is highly predictive of renal bone status (predictability is 93%).

(Ref. Monier-Faugere, Malluche, et. al., Kidney International, 2001; 60:1460-1468.)

4. How is the CAP™/CIP™ ratio value determined?

Each patient sample is tested with both a unique "intact" PTH assay (called "Total Intact PTH"), that measures both CAP™ (1-84 PTH) and CIP™ (7-84 PTH) equally (like total cholesterol measures LDL and HDL equally) and a CAP™ assay. Then the CAP™ assay value is subtracted from the "intact" PTH assay value to calculate the CIP™ (7-84 PTH) value. Finally, the CAP™ value is divided by the CIP™ value to calculate the CAP™/CIP™ ratio.

(Ref. Monier-Faugere, Malluche, et. al., Kidney International, 2001; 60:1460-1468.)

5. How many tests are needed to calculate the CAP™/CIP™ ratio?

There are 2 tests needed to generate the CAP™/CIP™ ratio. The first test is a direct test for CAP™ 1-84 PTH. The second test is a unique, 2nd generation Total Intact PTH test, in order to calculate CIP™ (CIP™ is the Total Intact PTH value minus the CAP™ value).

6. What does the current "intact" PTH test measure?

Biochemically, the "intact" PTH test measures PTH and its inhibitor as a combined value. This is like measuring the sum of insulin and glucagon and trying to use the value to predict carbohydrate metabolism. The term "intact" is a misnomer since the "intact" PTH assay is not measuring "intact" 1-84 PTH exclusively

Functionally, the "intact" PTH test is a poor predictor of bone status in the renal dialysis patient. Bone biopsy studies have demonstrated that if a patient has an "intact" PTH assay value of greater than 100 pgm/mL, the "intact" PTH assay value is a very poor predictor of renal bone status of high, normal and low bone turnover (overall predictability is only 73%).

7. Why does the SCL "intact" PTH value now always come out lower than the Nichols "intact" PTH assay value?

SCL has made the observation that in 2001, the SCL "intact" PTH values began to come out about 40% - 50% lower than the Nichols "intact" PTH assay values. In this year, Nichols published two Endocrine Society abstracts stating that the normal range for their "intact" PTH assay was 17-76 pgm/mL (previously reported as 10-65 pgm/mL). Also, in 2001, Nichols informed its customers that it had adjusted the calibration of its "intact" PTH assay. These actions may explain the differences between the SCL and Nichols "intact" PTH assays. It should be noted that the CAP™/CIP™ ratio is calculated from the "intact" PTH assay value.

(ref. Guthrie E. et. al., "Development of an Automated Assay that Measures 1-84 PTH with no Cross Reactivity to Non-(1-84) PTH." Abstract P3-115, presented at the Endocrine Society Meeting, Denver, CO, 2001. Guthrie E. et. al., "Measurement of Bioactive 1-84 PTH in Primary Hyperthyroidism". Abstract P3-116, presented at the Endocrine Society Meeting, Denver, CO, 2001. See also Nichols Customer Letter, dated May 14, 2001, re "standardization adjustment", on file at Scantibodies.)

8. What makes the Scantibodies CAP™ Assay unique?

Scantibodies CAP™ assay measures only 1-84 PTH and has no cross reactivity with 7-84 PTH fragments.

9. Can I use the Nichols intact and Bio-Intact PTH assays to generate the same CAP™/CIP™ Scantibodies ratio?

No. Scantibodies has comparative data from renal patients and there is no correlation between the Scantibodies and Nichols 1-84 PTH or CAP™ 1-84 PTH/CIP™ 7-84 PTH ratios. The comparative study data will be supplied upon request.

10. Is the CAP™/CIP™ ratio available from other laboratories?

The CAP™/CIP™ ratio is available in the USA only from Scantibodies Clinical Laboratory, Inc.--(SCL). ARUP Laboratory also provides the Scantibodies assays with the CAP™/CIP™ ratio by special agreement with Scantibodies.

11. How many replicates does SCL run for each Total Intact PTH and CAP™ assay?

SCL is a unique clinical laboratory in that it runs duplicate determinations on each patient sample (provided there is at least 1 ml of plasma sample available) for both the Total "Intact" PTH and CAP™ assays. Most other clinical laboratories run only single determinations on samples which make it impossible to see discrepancies revealed by imprecision of replicate determinations. SCL reports the mean of the duplicate PTH determinations. SCL automatically repeats PTH determinations at no charge if the replicates exceed the 10% CV limit.

12. What makes the SCL 2nd generation Total Intact PTH test unique?

In order to calculate the CIP™ value by subtracting the CAP™ value from the Total Intact PTH value, a unique, 2nd generation Total Intact PTH test must be used. This Total Intact PTH test must measure CAP™ (1-84 PTH) and CIP™ (7-84 PTH) on an equimolar basis. This means that the same amount of CAP™ (1-84 PTH) and CIP™ (7-84 PTH) will generate the same assay value in the unique, Scantibodies 2nd generation Total Intact PTH assay. This is not true of most 2nd generation "intact" PTH tests.


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Section II

INTERPRETATION OF PTH TEST RESULTS


1. How is the "intact" PTH assay value interpreted?

According to publications, if an "intact" PTH assay value is less than 100 pgm/mL, there is an 83% probability that the renal patient has adynamic low bone turnover disease. For patients with an "intact" PTH assay value of greater than 100 pgm/mL, the CAP™/CIP™ ratio can be helpful.

(ref. Monier-Faugere, Malluche, et. al., Kidney International, 2001; 60:1460-1468.) Qi Q, Monier-Faugere, et. al., Am J Kidney Dis 1995; 26:622-631.)

2. How should the CAP™ (1-84 PTH) and CAP™/CIP™ (1-84/7-84 PTH) values be interpreted?

"CAP™" is the term for 1-84 PTH, which is the hormone responsible for causing classical secondary hyperparathyroidism that gives rise to the high bone turnover condition. "CIP™", on the other hand, denotes the natural antagonist or the hormone which can give rise to the adynamic low bone turnover condition. When CAP™ (1-84 PTH) appears in great excess compared to CIP™ (7-84 PTH), then the high bone turnover condition of renal osteodystrophy can be the correct prediction. Conversely, when CIP™ (7-84 PTH) appears in excess over CAP™ (1-84 PTH)--(i.e., there is more circulating CIP™ 7-84 PTH compared to CAP™ 1-84 PTH or the CAP™/CIP™ ratio is less than one), then the adynamic low bone turnover condition can be the correct prediction. Based on evidence, one may conclude that an untreated patients CAP™/CIP™ ratio value of less than one indicates adynamic low bone turnover. When the CAP™/CIP™ ratio is greater than one, the untreated patient is in a normal or high bone turnover condition. When the CAP™/CIP™ ratio is "much greater than one", the patient is very likely to be in a high bone turnover status.

(ref. Monier-Faugere, Malluche, et. al., Kidney International, 2001; 60:1460-1468.)

3. How can the CAP™/CIP™ ratio assist in making therapeutic decisions (i.e., dosing of vitamin D, surgery, etc.)?

When "intact" PTH, CAP™ alone (without the ratio), osteocalcin and the CAP™/CIP™ ratio were compared to bone histology, the CAP™/CIP™ ratio was found to be by far the most useful non invasive predictor of adynamic low bone turnover disease versus normal/high bone turnover disease in patients.

(ref. Monier-Faugere, Malluche, et. al., Kidney International, 2001; 60:1460-1468.)

Minimally, this basic information gives direction as to when to titrate down suppressive therapy (i.e., vitamin D) due to adynamic low bone turnover disease. Titration details can be derived from package inserts of particular therapeutics.

4. How often should the CAP™ values and the CAP™/CIP™ Ratio be measured?

The first determination to establish is whether the patient is being initially diagnosed for an otherwise unsuspected disease, or whether the patient is being monitored for therapy. As a rule, diagnosis for unsuspected disease requires less frequent PTH testing as compared to testing for PTH to monitor therapy for secondary hyperparathyroidism. Diagnosis for unsuspected disease may be as infrequent as 1-2 times per year; whereas, therapeutic monitoring of PTH may be as frequent as monthly.

5. What CAP™/CIP™ ratio can be considered pathological?

In the clinical management of mineral metabolism disorders for the ESRD patient, it is clear that one of the most life-threatening conditions to avoid and address is adynamic low bone turnover disease, since this disease may contribute to soft tissue and vascular calcification. One of the greatest advances of the CAP™/CIP™ ratio over the flawed 2nd generation "intact" PTH assay is the ability to identify, without bone biopsy, adynamic low bone turnover disease in the ESRD patient, even if the patient has a high "intact" PTH value. Based on published bone histomorphological evidence, a ratio of less than one in an untreated ESRD patient can be used to predict adynamic low bone turnover disease.

(ref. Monier-Faugere, Malluche, et. al., Kidney International, 2001; 60:1460-1468)

6. How can there be an abnormal CAP™/CIP™ ratio when the PTH level is normal?

The normal range for the "intact" PTH assay within the normal population with functioning kidneys, is 10-65 pgm/mL. It has been learned that the ESRD patient population is associated with much higher levels of "intact" PTH assay values. The broad, somewhat arbitrary "intact" PTH range of approximately five times normal or 100-300 pgm/mL has been used as a rough target for PTH management in the ESRD population. However, it has been found that a patient with an "intact" PTH value of greater than 100 pgm/mL may have high, normal or adynamic low bone turnover status. We can use the 2nd generation "intact" PTH assay to predict the abnormality of adynamic low bone turnover ONLY if the "intact" PTH value is less than 100 pgm/mL. But we cannot use the "intact" PTH assay for renal bone status prediction if the value is greater than 100 pgm/mL. Therefore, if a patient has an "intact" PTH value of less than 100 pgm/mL, the ratio is not needed. If the "intact" PTH value is greater than 100 pgm/mL, then the CAP™/CIP™ ratio is needed.

(ref. Monier-Faugere, Malluche, et. al., Kidney International, 2001; 60:1460-1468. Qi Q, Monier-Faugere, et. al., Am J Kidney Dis 1995; 26:622-631.)

7. How soon after a change is made in calcium or vitamin D dosing should PTH values change?

Changes in PTH occur within minutes after calcium changes in the blood. However, changes in the bone morphology resulting from changes in PTH require 3-6 months. This is the advantage of measuring PTH more frequently since changes in bone morphology can be controlled before they occur by controlling PTH secretion.

8. What happens to the CAP™/CIP™ ratio when the dose of vitamin D or calcium is decreased?

Faugere, et. al., have demonstrated that when calcium is increased within physiological limits in a dialysis patient, that the CAP™/CIP™ ratio decreases.

(ref. Monier-Faugere, Malluche, et. al., Kidney International, 2001; 60:1460-1468.)

It has been demonstrated that administration of vitamin D seems to increase the predominant secretion of CIP™ (7-84 PTH) over CAP™ (1-84 PTH).

(ref. Kazama JJ., et. al., "Hypocalcemic 7-84 PTH Fragment Level Increases with Vitamin D Treatment." Abstract submitted for ERA-EDTA Annual Congress, July, 2002, Copenhagen, Denmark.)

Moreover, it has been typically observed by SCL that when vitamin D is decreased in an ESRD patient, the CAP™/CIP™ ratio increases. This makes sense if we consider CIP™ (7-84 PTH) as the parathyroid glands hormonal messenger to lower serum calcium.

9. How should the CAP™/CIP™ ratio be considered in prescribing parathyroidectomy?

The CAP™/CIP™ ratio can be useful in predicting bone turnover condition in the ESRD patient with secondary hyperparathyroidism. However, a comprehensive evaluation of the spectrum of clinical indications and laboratory test results should be included before parathyroidectomy is prescribed. The poor renal bone status predictive value of the flawed, 2nd generation "intact" PTH assay should be taken into consideration before being relied upon. For accurate renal bone assessment before parathyroidectomy, a bone biopsy should be considered.

10. What is adynamic low bone turnover disease and why has it been increasing over the years?

Adynamic low bone turnover is the abnormal state wherein the bone is remodeling at a less than optimal rate. The reason(s) for its increasing prevalence has not been elucidated.

11. What is the gold standard and how do you determine which PTH test is best for determining bone status in the ESRD patient?

The gold standard for determining renal bone disease is histomorphemetry derived from a bone biopsy. Bone biopsies are useful for an accurate snapshot of bone status (particularly as a confirmation before parathyroidectomy). But, monitoring therapy via multiple bone biopsies is not practical.

12. Why are there so few studies that correlate PTH tests to bone biopsies?

Bone biopsy studies are rare, as many patients are not willing to submit to bone biopsies.

13. What does it mean if a patient has troublesome high values in the "intact" PTH assay that cannot be suppressed with vitamin D?

The "intact" PTH assay value is made up of CAP™ (1-84 PTH) and CIP™ (7-84 PTH). It is important to find out if the proportion of CAP™ (1-84 PTH) is much higher than CIP™ (7-84 PTH). If the proportion of CAP™ (1-84 PTH) is less than CIP™ (7-84 PTH), although "intact" PTH may be high, the patient may be over-suppressed.

(ref. Slatopolsky et. al., Kidney International 2000; Vol.58:753-761. Monier-Faugere, Malluche, et. al., Kidney International, 2001; 60:1460-1468.)

14. Is this new PTH test only for renal bone disease?

More than 80% of ESRD patients have renal bone disease. Moreover, renal bone disease may lead to soft tissue calcification arising from abnormal levels of the calcium phosphate product. The management of PTH is important for both the control of renal bone disease and, indirectly, for the control of soft tissue calcification.

15. What is the evidence for calcification?

One of the evidences for increasing rates of calcification is an increase in the prevalence of calciphylaxis nodules.

16. Does an over-administration of vitamin D pose a risk of calcification?

It is not uncommon to find in package inserts for vitamin D analogues, a warning that over-administration of vitamin D can result in soft tissue calcification.

17. How could the "intact" PTH assay results mislead and result in the over-administration of vitamin D?

High "intact" PTH values have been demonstrated

with bone histology to be associated with both normal and adynamic low bone turnover. If a patient has a high "intact" PTH value with normal or adynamic low bone turnover disease, this might lead to an over-administration of vitamin D.

18. Is calcification reversible?

Little evidence exists that would support the premise that calcification is reversible.

19. Is calcification life threatening?

Vascular calcification can be scored with EBCT (Electron Beam Computer Tomography). There is a strong correlation between mortality and increasing EBCT scores.

(ref. Blacher J, Hypertension, 2001; 38:938-942).

20. How soon does vascular calcification begin for the dialysis patient?

In young adults, vascular calcification can start in less than 2 years from the start of dialysis.

(ref. Goodman, et. al., "Coronary-Artery Calcification in Young Adults with End-Stage Renal Disease Who Are Undergoing Dialysis." NEJM 2000; 342:1478-1483.)

21. Has anyone else (other than Dr. Malluche) confirmed the correlation of the 1-84/7-84 PTH ratio with bone histology?

Yes, per Drs. Salusky & Goodman, et. al., "Relationship between a 3rd generation assay for PTH and bone formation in children on dialysis" JASN 2001; 12:772A, Abstract A4032. Here is a key quote: "The ratio ILMA-PTH/NHT was < 1 in all but 2 HT, while the ratio was < 1 in 6 of 8 NL/LT, p<0.025." (HT=High Turnover, NL=Normal, LT=Low Turnover).



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Section III

PROCESSING THE PTH BLOOD SAMPLES

1. What is wrong with shipping whole blood as a sample to a central laboratory for PTH testing?

PTH is a labile hormone with a half-life in circulation of less than five minutes. Publications have documented that EDTA-preserved whole blood does not give the same PTH results as freshly centrifuged and frozen plasma. Therefore, freshly centrifuged and frozen EDTA plasma is the sample that Scantibodies uses for generating PTH assay values.

(ref. Omar H, et. al., Ann Clin Biochem 2001; 38:561-563.)

2. What is an FDA-approved PTH kit package insert?

The U.S. Food and Drug Administration (FDA), regulates PTH test kits. This means that all PTH test kits for clinical diagnostics in the USA must be approved by the FDA before they can be sold across state lines. Both the CAP™ assay and the Total Intact PTH assay that Scantibodies has discovered and developed have been approved by the FDA.

Included in the FDAs review and approval are the PTH test kit instructions, also known as the package insert or labeling. A package insert for a PTH test kit cannot be changed by a manufacturer without the approval of the FDA. An integral part of these package inserts is the specimen requirement which includes whether or not the specimen may be stored (i.e., shipped) as whole blood prior to centrifugation.

(ref: CFR Title 21, Food and Drugs)

3. Who is responsible for making decisions regarding the medical necessity for and type of patients testing?

The primary care physician (i.e., the nephrologist for the ESRD patient) is responsible for making decisions of medical necessity for his/her patients.

4. What is the correct specimen to draw for the CAP™/CIP™ ratio?

SCL requires that an EDTA (lavender top tube) blood sample with a minimum of 2 ml of blood be drawn and centrifuged within 60 minutes and frozen, in order to derive EDTA plasma for performing both the unique "Total Intact PTH" and "CAP™ Assay" tests in order to calculate the CAP™/CIP™ ratio.

5. What needs to happen to the blood sample after it is drawn for the CAP™/CIP™ ratio?

Once the EDTA (lavender top) blood sample has been drawn, it must be centrifuged within one hour to separate the red blood cells from the plasma. The plasma is then pipetted off the cells into a labeled transfer tube which is frozen in a non-defrosting freezer. Then the sample is transported on dry ice (supplied by SCL) to SCL for testing.



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Section IV

BILLING FOR PTH TESTS

1. Does the CAP™/CIP™ ratio represent double billing?

No. Medicare and other insurances reimburse for tests performed as deemed "medically necessary" by the primary care physician. The two tests for which SCL bills are the Total Intact PTH test and the CAP™ test. There is no billing for the calculated values of CIP™ 7-84 PTH or the CAP™/CIP™ ratio.

2. Is the same CPT code used for both the "intact" PTH test and the CAP™ test?

Yes. There are many instances where several tests are performed on the same sample and only one CPT code is available for billing for the different tests. Some examples are: PSA and free PSA (for calculation of PSA ratio); HDL and cholesterol (for calculation of the LDL/HDL ratio); toxo IgM and toxo IgG; dander IgE and ragweed IgE, etc.

3. Does Medicare reimburse for "intact" PTH and CAP™ tests and the CAP™/CIP™ ratio?

Medicare reimburses for medically necessary tests as determined by the primary care physician. Therefore, if it so ordered by the primary care physician, Medicare reimburses for the "intact" PTH and CAP™ tests on the same sample in order to determine the CAP™/CIP™ ratio. Medicare does not reimburse and SCL does not bill for calculated values of CIP™ (7-84 PTH) or the CAP™/CIP™ ratio.

4. Does the Total Intact PTH test and CAP™ Assay cost more than the old "intact" PTH test?

SCL bills for two tests: "Total Intact PTH" and the "CAP™ Assay". Each test costs the same as the traditional "intact" PTH test.

5. Who does the billing for the SCL Total Intact PTH and CAP™ tests for Medicare patients?

SCL bills Medicare directly for the Total Intact PTH and CAP™ tests necessary for calculating the CAP™/CIP™ ratio.

6. Is SCL an accredited laboratory?

Yes. SCL is accredited with the U.S. Dept. of Health and Human Services according to CLIA regulations. SCL is also accredited at the state and local levels. Click here to view our licenses and accreditations.


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Section V

OTHER PTH TESTS

1. Has any other biochemical test been demonstrated to be superior to the CAP™/CIP™ ratio for predicting renal bone disease?

No. Even measuring CAP™ (true 1-84 PTH) alone (without the ratio) was not as predictive of renal bone disease as the CAP™/CIP™ ratio.

(ref. Monier-Faugere, Malluche, et. al., Kidney International, 2001; 60:1460-1468.)

2. Are assays from other companies for CAP™ (1-84 PTH) and the CAP™/CIP™ ratio all the same?

In order for another company to be able to generate SCL's CAP™/CIP™ ratio, both the "intact" PTH assay and the CAP™ assay must be identical to SCL's. So far, no company has been identified by SCL to be successful in duplicating the SCL CAP™ and Total Intact PTH assays. Therefore, ratios from other companies do not match the SCL CAP™/CIP™ ratio.

3. Why doesnt SCL enable other laboratories to actually perform these new PTH tests?

In the mid 1970's, the founder of Scantibodies developed first generation PTH assays. In the 1980's, Scantibodies produced the first 2nd generation PTH assay antibodies for Nichols. In the 1990's, Scantibodies discovered, developed, published and filed for patents on the 3rd generation PTH assays. Scantibodies Clinical Laboratory is a PTH reference lab that provides results in a way that is not the norm for the majority of testing laboratories. Unlike most testing laboratories, SCL runs its PTH tests from specimens that have been centrifuged immediately after blood draw. Then the EDTA plasma is immediately frozen and transported to the lab for testing. PTH tests are run in duplicate and our report is the mean of duplicates. Moreover, Scantibodies has played an active role in the discovery and development of the 3rd generation PTH assays. In order to preserve the integrity of this new PTH technology, only Scantibodies Clinical Laboratory offers these new PTH tests in the United States.


Section VI

QuantiFERON®-TB Gold TEST

1. Why QuantiFERON®-TB Gold (QFT-Gold) versus tuberculin skin test (TST)?

• QFT-Gold requires one visit versus TST which requires 2 visits (one to have it placed and one to have it read)

• QFT-Gold is objective, Yes or No answer versus TST is subjective to open reader bias/interpretation

• QFT-Gold is a blood test with no possibility of side effects versus TST where tuberculin is placed in your skin and could cause adverse reactions

2. How does it work?

Blood samples are mixed with antigens and incubated for 16 to 24 hours. The antigens include ESAT-6 and CFP-10, proteins specific to M. Tuberculosis complex. These antigens are not found in BCG strains or M. avium.

If the patient is infected with M. tuberculosis, the patient’s lymphocytes will recognize the antigens and release interferon-gamma (IFN-g) in response. The QFT-Gold results are based on the amount of IFN-g that is released.

3. What is the difference between active and latent TB?

Tuberculosis (TB) is a disease caused by bacteria called Mycobacterium tuberculosis. The bacteria usually attack the lungs, but TB bacteria can attack any part of the body such as the kidney, spine, and brain.

  • Active TB Disease
    TB is spread through the air from one person to another. A person with active TB is contagious and symptoms may include coughing, unexplained weight loss, night sweats, fever, chills, no appetite and fatigue.
  • Latent TB Infection
    People infected with latent TB do not feel sick, are not contagious and show no symptoms, but mycobacterium remains inactive in the body.

4. When should you use the QuantiFERON®-TB Gold (QFT-Gold)?

QFT-Gold can be used in all circumstances in which the TST is used.

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