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We are also seeing 30-40% lower values with new PTH assay. We have not completed the reference range study, but it is ironic to see that DPC is providing about the same reference ranges for both kits. The question is if the new ranges are right, were previous ranges provided wrong!!! Uttam Garg, PhD, DABCC Associate Professor Director of Clinical Chem & Tox Labs Children's Mercy Hospital Kansas City, MO 64108 Phone: 816-234-3803 Fax: 816-234-3794 > -----Original Message----- > From: Collins, Wayne [SMTP:[log in to unmask]] > Sent: Tuesday, November 06, 2001 8:09 AM > To: [log in to unmask] > Subject: DPC Immulite new PTH assay Cat No. LKPP1 or LKPP5 > > Reviewing the evaluation data for this new PTH kit I have certain concerns > over the 30% decrease in values over the current (but soon to be > unavailable) kit. As well as a reformulation of the antibodies, there is > now > also a marked downward shift in results, presumably due to recalibration > of > the assay.The DPC data sheet shows good agreement of the new kit with the > Nichols Chemiluminescent and IRMA methods. Is this perhaps the sole > justification for the apparent recalibration of the method ?? > > My other concern is the reference range stated in the DPC insert: this is > virtually identical for the new and old PTH kits, in spite of a 30 % > difference in results. Square pegs and round holes come to mind. > > In the September 2001 NEQAS return for PTH there are 18 laboratories > returning results for the new DPC kit (Immulite plus Immulite 2000). I > would > be interested to know what reference range these people use and their > opinions (or anyone else) on manufacturers making such major shifts in > calibration. Is this another case of manufacturers chasing each to obtain > similar EQAS results ? > > Wayne Collins > Royal Preston Hospital