Transfer of Tumor Marker Assays to the
IMMULITE® 2000
A Laboratory Perspective

Making the switch to a new vendor can often prove worthwhile in many ways, but achieving a smooth transition is sometimes easier said than done. Following a strategic plan, however, can minimize potential hurdles, which is exactly what we discovered during our recent conversion to DPC's IMMULITE^® 2000 tumor markers at the Mid-Western Regional Hospital in Limerick, Ireland. Thanks to our highly successful strategy and DPC's product support, our transition was a very positive experience.

With a total of 552 inpatient beds, the hospital serves a population of 340,000 and treats approximately 33,700 inpatients, 118,600 outpatients and 50,300 acute/emergency patients annually. The clinical biochemistry workload at our regional laboratory during 2002 consisted of almost 1.75 million tests, 36 percent being associated with primary care.

The system procurement was prompted by a significant increase in workload due, in large part, to the hospital's use of investigative protocols for oncology (including prostate cancer and hematological malignancies), allergy, thyroid, reproductive endocrinology, type 2 diabetes, ischemic heart disease risk assessment and the intensive monitoring of long-term conditions.

Procurement Objectives
	Achieving greater capacity and productivity
	Acquiring twin systems with benefits of
	- Operational and analytical flexibility
	- Backup during downtime
	- Analytical consistency
	Improving quality of service
	Optimizing total cost
	Securing the best available value
	Rationalizing contractual arrangements

Ultimately, we at Mid-Western Regional Hospital made the decision to purchase two IMMULITE 2000 systems on the basis of menu, functionality, immunoassay track record and total life-cycle cost over five years. In so doing, we replaced our Bayer ACS:180^®, which ran all endocrine assays and HCG, and our Abbott AxSYM^®, which ran the other tumor marker tests.

Tasks associated with installation of the new systems were conducted in phases. Once the basics were addressed, we proceeded to establish a proactive plan for defusing and resolving issues that were sure to arise from the replacement of our tumor marker assays. Initially, we conducted exploratory correlation studies with existing assays, examined EQA (external quality assessment) performance, compared reference values and studied US FDA and other evaluation reports. Four of the assays (HCG, PSA, AFP, CEA) required no strategic tactics, as they correlated closely with existing methods and reference values were the same. The other three assays (BR-MA, GI-MA, OM-MA) posed several challenges, however, necessitating a detailed transitional plan.

Clear and consistent communication with laboratory users was the key to the efficient manner in which we replaced the CA15-3, CA19-9 and CA125 tumor marker assays with DPC's BR-MA, GI-MA and OM-MA assays, respectively. All laboratory users were informed of the arrangements for the changeover and the new analyte names. A transitional 90-day overlap period was established, with dual reporting of both old and new results displayed side-by-side for each patient. Dual tracking, for example, of individual ovarian cancer patients revealed highly similar patterning between OM-MA and CA125. Trends for these individual patients were carefully monitored throughout the transitional period, and regular communication was maintained with the Medical Oncology Team.

Being prepared to address physicians' questions was another key component of our strategy. An appraisal of graphical presentations of the data yielded closely correlating trajectories for the vast majority of samples, while emphasizing the need for reconciling differences between cutoff values. Comparison studies yielded the statistics listed below.

(IMMULITE 2000 BR-MA) = 1.21 (Abbott CA15-3) + 9.22 r2 = 0.98, n = 96, range 10 - 1260 kU/L

(IMMULITE 2000 GI-MA) = 1.06 (Abbott CA19-9) + 0.95 r2 = 0.97, n = 327, range 2.5 - 3021 kU/L

(IMMULITE 2000 OM-MA) = 0.85 (Abbott CA125) - 5.1 r2 = 0.98, n = 513, range 2.1 - 13360 kU/L

Anticipating potential concerns over a change in cutoff values, however, we drafted the following statement for requesting physicians: "While results from the new assay may differ in numerical value when compared with the old assay, they will respond to treatment in the same manner."

With regard to questions surrounding the actual antigens measured by BR-MA, GI-MA and OM-MA, we made sure the physicians understood that each of these assays detects an antigen similar to its respective counterpart (CA15-3, CA19-9, CA125). While making it clear that from a clinical standpoint, the assays are equally effective for patient monitoring and follow-up, we also made a point of noting that ". . . none of these markers has absolute organ specificity and none is specific for malignancy." Incidentally, US FDA approvals for some tumor markers do not always include all the applications utilized by clinical oncologists in countries outside the US.

Our concluding analysis indicated that patient care had not been adversely impacted and the transition provided a learning opportunity for users. In addition, system functionality and reagent usage were as expected and expenditure was on target. The end result was more effective workload management-the very goal we set out to accomplish. Having achieved an economical solution to our workload problem, without any repercussions in terms of patient care, we validated our buying decision and have successfully enhanced our service to the physicians.

Reference
Barrett EJM. Management of issues associated with the transfer of Abbott CA15-3, CA19-9 and CA125 tumour marker assays to the IMMULITE 2000 system [poster]. In: Martin SM, editor. Proceedings of the ACB National Meeting Focus 2003; 2003 May 13-15; Birmingham, UK. London, UK: Association of Clinical Biochemists; 2003. p. 57.