Chiron Diagnostics Research Articles

VacA seropositivity is not associated with the development of gastric cancer in a Japanese population.

Infection with Helicobacter pylori strains producing vacuolating cytotoxin (VacA) is associated with enhanced gastric mucosal damage and the development of gastric mucosal atrophy. The aim of this study was to investigate whether VacA seropositivity is associated with increasing risk of gastric cancer in Japanese populations which have much higher incidence of gastric cancer than Western populations. Serum sample was collected from 81 patients with gastric cancer and 81 sex- and age-matched endoscopically evaluated control subjects. Histologically, 62 cancers were of the intestinal type and 76 were early gastric cancer. H. pylori and VacA IgG antibodies were assayed by Western blotting using Chiron Diagnostics' Recombinant Immunoblot Assay (RIBAa). VacA seropositivity was 68% (55/81) in patients with gastric cancer and 70% (57/81) in controls. The odds ratio for the risk of gastric cancer in VacA seropositives was 0.89 (95% CI 0.46-1.74). In H. pylori seropositive patients and their control subjects (matched H. pylori-positive controls), VacA seropositivity was the same 80.6% (50/62). The odds ratio for the risk of gastric cancer in H. pylori-positive patients if VacA seropositive was 1.00 (95% CI 0.41-2.44). The mean relative intensity of VacA antibody titre was 3.01+/-0.18 in the 55 VacA seropositive cancer patients and 3.09+/-0.17 in the 57 VacA seropositive control subjects (difference not significant). These results suggest that VacA seropositivity is not associated with increasing risk of gastric cancer in Japanese populations.

LIVER TRANSPLANTATION IN ASIAN PATIENTS WITH CHRONIC HEPATITIS B USING LAMIVUDINE PROPHYLAXIS

367 PURPOSE: We studied the efficacy and safety of a nucleoside analogue lamivudine in prophylaxis against recurrent hepatitis B (HBV) in Asian patients after liver transplantation (LTx). METHODS: From September 1995 to September 1998, 27 Asian patients (age 17-60yr; M:F, 24:3) who were positive for HBsAg from chronic HBV underwent primary LTx using lamivudine prophylaxis. Ten (37%) patients were of UNOS status 1 and 6 (22%) had associated hepatocellular carcinoma. Fifteen patients received oral lamivudine (100 mg daily) for > 30 days (median, 90 days; 54-374 days) before LTx and 12 underwent LTx within 7 days (median, 4 days; 1-7 days) of lamivudine treatment. Sixteen patients were HBeAg-positive and 9 HBVDNA-positive (Quantiplex™ bDNA assay, Chiron Diagnostics) before lamivudine treatment. Six of 16 patients cleared HBeAg and 5 of 9 cleared HBVDNA before LTx. Lamivudine prophylaxis was continued after LTx and Hepatitis B immunoglobulin was not used. RESULTS: Five patients died of causes not related to HBV at 5 to 36 days after OLT. The remaining 22 (82%) patients were followed-up for a median of 15 months (4 to 39 months) after LTX. There was no adverse effect attributed to lamivudine. In 7 patients, HBsAg persisted or reappeared after a period of temporary clearance, and 15 patients remained HbsAg-negative at a median of 17 months after LTx. One (4.5%) patient developed recurrent hepatitis due to a mutant strain at the YMDD locus 397 days after LTx. There was no biochemical or histologic evidence of recurrent hepatitis B in the remaining 21 patients and none had detectable HBVDNA (by PCR) in serum at a median of 17 months (4 to 39 months) after LTx. CONCLUSIONS: At a median follow-up of 15 months, Lamivudine monotherapy is safe and effective in preventing recurrent hepatitis B following LTx in Asians.

ProbeDesigner: for the design of probesets for branched DNA (bDNA) signal amplification assays.

The sensitivity and specificity of branched DNA (bDNA) assays are derived in part through the judicious design of the capture and label extender probes. To minimize non-specific hybridization (NSH) events, which elevate assay background, candidate probes must be computer screened for complementarity with generic sequences present in the assay. We present a software application which allows for rapid and flexible design of bDNA probesets for novel targets. It includes an algorithm for estimating the magnitude of NSH contribution to background, a mechanism for removing probes with elevated contributions, a methodology for the simultaneous design of probesets for multiple targets, and a graphical user interface which guides the user through the design steps. The program is available as a commercial package through the Pharmaceutical Drug Discovery program at Chiron Diagnostics.

Effect of the hemoglobin-based oxygen carrier HBOC-201 on laboratory instrumentation: cobas integra, chiron blood gas analyzer 840, Sysmex SE-9000 and BCT.

As part of a clinical trial, we evaluated the effects of the hemoglobin-based oxygen-carrier (HBOC) HBOC-201 (an ultrapurified, stroma-free bovine hemoglobin product, Biopure, Cambridge, MA, USA) on our routine clinical chemistry analyzer (Cobas Integra, F. Hoffmann-La Roche Ltd, Basel, Switzerland ), blood gas analyzer (Chiron 840, Chiron Diagnostics Corporation, East Walpole, MA, USA), routine hemocytometry analyzer (Sysmex SE-9000, TOA Medical Electronics Co Ltd., Kobe, Japan), hemostasis analyzer (BCT, Dade-Behring, Marburg, Germany) and bloodbanking system (Dia-Med-ID Micro Typing System, DiaMed AG, Cressier, Switzerland). The maximum tested concentration of HBOC-201 was 65 g/l. Of the 27 routine clinical chemistry tests challenged with HBOC-201, bilirubin-direct, creatine kinase MB-fraction (CK-MB), creatine kinase (CK), gamma-glutamyltransferase (GGT), magnesium and uric acid were influenced by even low concentrations of HBOC-201. These tests were excluded from use on the plasma of patients treated with HBOC-201. Since the non-availability of the cardiac marker CK-MB may lead to problems in acute situations, we introduced the qualitative Trop T-test (Boehringer Mannheim), which was not influenced. The applicability of another nine tests was limited by the concentration of the HBOC-201 in the patients' plasma. No interference of HBOC-201 in routine hemocytometry, hemostasis-analysis and red-blood cell agglutination detection (blood-bank tests) was observed. Although immediate patient-care was not compromised, routine use of hemoglobin-based oxygen carriers will have a strong impact on logistical management. The development of robust laboratory tests free from the interference of the pigmented oxygen carriers should therefore precede its introduction into routine transfusion medicine.

A comparison of three free and total PSA assays.

Prostate-specific antigen (PSA) has emerged as the most predictive test of whether or not a man has prostatic carcinoma. The free to total PSA ratio provides important enhancement in specificity, thus obviating unnecessary negative biopsies. In the absence of an international standard for total PSA, much less free PSA, variation between manufacturers may cause confusing results. We sought to compare three different manufacturer's free and total PSA assays in a population consisting of consecutive patients who had PSA testing in a reference laboratory in Germany. Between April 1994 and July 1996, serum specimens from 240 men were evaluated with three different free and total PSA assays. Indications for PSA determination were based on the referring physician, who also provided the clinical diagnosis. Total and free PSA were measured on the same freeze-thaw cycle with Chiron Diagnostics, Enzymun Boehringer Mannheim, and Hybritech Tandem-R assays. Seventy-nine men had carcinoma of the prostate, 120 had clinical evidence of benign prostatic hyperplasia and 27 were without evidence of prostatic disease. The Chiron ACS: 180 free to total ratio compared very well with the Tandem-R assay at the 95% sensitivity level, affording 17 and 22% specificity respectively. Using the range of total PSA of 4-10 ng/ml, the increase in specificity of the free to total PSA is quite significant, and the specificity of the Enzymun assays is greatly improved. (Specificity of 49%, 29% and 25% at 95% sensitivity for ACS, Enzymun and Tandem respectively.) This data, based on 'real world' clinical experience, shows significant variation between different manufacturers' assays. There was significant equivalence between the Chiron and Hybritech assays. The Enzymun assay performed well only when data from the total PSA range of 4-10 ng/ml was included. Clinicians must be aware of which manufacturers' assays for both the free and total PSA their laboratory staff is utilizing, and laboratory technicians must provide meaningful outcome data based on the patient population they serve with respect to the performance of these assays.

Sequential serum hepatitis C viral RNA levels longitudinally assessed by branched DNA signal amplification.

The aim of this study was to determine the stability of viral load over an extended period in patients with chronic hepatitis C virus (HCV). Sequential serum specimens collected from fourteen non-alcoholic adult patients with chronic HCV between 1990 and 1997 were tested retrospectively for HCV RNA levels by branched DNA assay (Quantiplex HCV RNA 2.0 [Chiron Diagnostics, Emeryville, CA]). A minimum of three serum samples was obtained at various intervals from each patient. None of the patients received antiviral therapy. Liver biopsies, available for 10 of 14 patients, showed mild or moderate hepatitis in seven and cirrhosis in three (one developed cirrhosis during follow-up). RIBA strip immunoassay showed that 7, 3, and 4 patients had viral genotypes 1, 2, and 3, respectively. The follow-up time averaged 5.3 years (range, 3.7 to 6.6 years). Eight patients (57.2%) showed increased viral levels from baseline to follow-up, the remaining six patients (42.8%) showed decreased viral levels. The three cirrhotic patients had the highest viral levels over time. The mean change was a 0.29-fold decrease (median, +1.14 [corrected]; range, -17.49 to +7.32). A less than twofold change in either direction was demonstrated for six patients (42.8%), and a less than threefold change was demonstrated for 10 patients (71.4%). Variation from baseline to last follow-up as calculated by log determination showed that the viremic load varied less than one log10 in all but one individual. These results show that viral load remains relatively stable over prolonged periods in most untreated patients with chronic hepatitis C.

Evaluation of Two Automated Immunoassays for Measurement of Free Deoxypyridinoline in Urine Using Analytical Goals Derived from Biological Variation

Free deoxypyridinoline (fDPD) is increasingly used as a specific marker of bone resorption (1). To date, the concentration of fDPD in urine has been measured using cumbersome HPLC or manual microtiter-based ELISA procedures, which require ∼4 h to perform (2). Recently, two rapid, fully automated chemiluminescent immunoassays were developed: by Chiron Diagnostics for the ACS:180® analyzer and by DPC® for the Immulite® analyzer. Both immunoassays use a competitive format involving the same monoclonal anti-fDPD antibody from Metra Biosystems (3)(4). If sufficiently reliable, these assays can accommodate increasing testing demands with both controlled operating …

Rapid and Automated Assay for Thyrotropin in Guthrie Cards on the ACS:180

Congenital hypothyroidism causes a decreased growth rate and skeletal development and can lead to severe mental retardation (1). In the nearly three decades since measurement of thyroxine in filter paper dried blood disks (Guthrie cards) was introduced as a method to screen newborns for congenital hypothyroidism (2), new procedures for thyroxine and thyrotropin (TSH), such as ELISA, fluoroimmunoassay, or chemiluminescence (3) have been developed or adapted from commercial kits, most of them requiring overnight incubation. Previously, we described a manual adaptation of a commercial immunochemiluminometric assay kit based on an acridinium label to measure TSH in dried blood spots (4). This method is used routinely in our laboratory, and we have detected 176 congenital hypothyroidism cases in the 480 000 newborn samples tested. Studies concerning its correlation with the DELFIATM neonatal TSH kit (Wallac Oy) were also described (5). Here, we present results obtained with a rapid and automated third-generation TSH chemiluminescent assay for serum samples adapted to measure TSH in Guthrie cards (ACS:180TM, Chiron Diagnostics). This fully automated chemiluminescence immunoassay system uses paramagnetic particles as the solid phase (6). We measured TSH in 2200 dried blood spot samples obtained in filter paper (Schleicher and Schuell, cat. no. 903) by heel stick from newborns routinely referred to our service. The samples were dried at room temperature, and the TSH concentrations were measured using our routine chemiluminescent method (4) and also by the technique described here. We used calibrators at 2.2, 22.0, 55.0, 110.0, 220.0, and 550.0 mIU TSH/L serum equivalent and controls at 33.0 and 132.0 mIU TSH/L serum equivalent provided with the DELFIA …

Comment on the Nature and Specificity of Bayer Corporation and Chiron Diagnostics hCG Immunoassays

We wish to update information in the recent hCG review article (1) , regarding the specificities and antibody configurations used in the Chiron Diagnostics and Bayer Corporation hCG immunoassays. The review article depicted the diverse nature of the human chorionic gonadotropin (hCG) molecule. As described, a non-nicked hCG (the hormone), a nicked hCG, a free α-subunit, and a free β-subunit are present in blood samples, and the same molecules plus a β-core fragment occur in urine samples. As described in the review article (1) , commercial hCG assays sold in the United States use a variety of antibodies directed to different sites on hCG and related molecules. Some assays …

Chiron 800 System CO-oximeter Module Overestimates Methemoglobin Concentrations in Neonatal Samples Containing Fetal Hemoglobin

Inhaled nitric oxide (NO) is an established treatment for persistent pulmonary hypertension of the newborn (1). NO can oxidize erythrocyte hemoglobin Fe(II) to Fe(III), however, and can lead to potentially toxic accumulation of methemoglobin (MetHb) (2). Because MetHb fractions >5% can lead to toxicity, monitoring of MetHb throughout therapy is required. In one exceptional case, excessive dosing of NO led to a MetHb fraction of 40% (3). Because neonatal blood contains a high proportion of fetal hemoglobin (HbF), typically 75–90% at term (4), accurate measurement of MetHb in the presence of HbF is essential. We wished to ascertain the accuracy of MetHb determination by the Chiron 800 system CO-oximeter module (Chiron Diagnostics), part of their 865 analyzer, in the presence of high HbF. A similar study of …

Sequential serum hepatitis C viral RNA levels longitudinally assessed by branched DNA signal amplification

The aim of this study was to determine the stability of viral load over an extended period in patients with chronic hepatitis C virus (HCV). Sequential serum specimens collected from fourteen non-alcoholic adult patients with chronic HCV between 1990 and 1997 were tested retrospectively for HCV RNA levels by branched DNA assay (Quantiplex HCV RNA 2.0 [Chiron Diagnostics, Emeryville, CA]). A minimum of three serum samples was obtained at various intervals from each patient. None of the patients received antiviral therapy. Liver biopsies, available for 10 of 14 patients, showed mild or moderate hepatitis in seven and cirrhosis in three (one developed cirrhosis during follow-up). RIBA strip immunoassay showed that 7, 3, and 4 patients had viral genotypes 1, 2, and 3, respectively. The follow-up time averaged 5.3 years (range, 3.7 to 6.6 years). Eight patients (57.2%) showed increased viral levels from baseline to follow-up, the remaining six patients (42.8%) showed decreased viral levels. The three cirrhotic patients had the highest viral levels over time. The mean change was a 0.29-fold decrease (median, +1.14 [corrected]; range, -17.49 to +7.32). A less than twofold change in either direction was demonstrated for six patients (42.8%), and a less than threefold change was demonstrated for 10 patients (71.4%). Variation from baseline to last follow-up as calculated by log determination showed that the viremic load varied less than one log10 in all but one individual. These results show that viral load remains relatively stable over prolonged periods in most untreated patients with chronic hepatitis C.

Cross-Reactivity of Fosphenytoin in Four Phenytoin Immunoassays

Fosphenytoin, 5,5-diphenyl-3-[(phosphonooxy)methyl]-2,4-imidazolidine-dione disodium salt (Cerebyx®; ParkeDavis), is a phosphorylated form of the anticonvulsant drug phenytoin. Fosphenytoin itself has no pharmacological activity but is dephosphorylated in vivo by phosphorylases to the active drug, phenytoin. The elimination half-life of fosphenytoin in plasma is 8–15 min in healthy subjects (1)(2). Fosphenytoin can be used for parenteral or intramuscular administration, where its superior aqueous solubility results in less severe side effects than does phenytoin (2)(3). Few data, however, are available on the interference of fosphenytoin in phenytoin immunoassays, which are currently the most common method used to monitor patients’ phenytoin concentrations. In an abstract (4), Kugler et al. reported that the TDx® Phenytoin assay (Abbott Labs.) was interfered with by fosphenytoin. We report here the results of detailed cross-reactivity studies for fosphenytoin in four phenytoin im-munoassays: ACS:180® Automated Chemiluminescence System (Chiron Diagnostics), TDx Phenytoin and Phenytoin II, and AxSym® Phenytoin II …

Reagents with enhanced performance in clinical diagnostic systems: Abel, AL; D'Orazio, P; Dalzell, B; McCaffrey; R & Uretsky, L (Chiron Diagnostics Corporation, USA), US 5667983, October 1997

Reagents with enhanced performance in clinical diagnostic systems: Abel, AL; D'Orazio, P; Dalzell, B; McCaffrey; R & Uretsky, L (Chiron Diagnostics Corporation, USA), US 5667983, October 1997

108 STABILITY DIGOXIN AND DIGITOXIN IN SPECIMENS COLLECTED IN VACUTAINER BLOOD COLLECTION TUBE

Chiron Diagnostics, Walpole, MA, and Department of Pathology, University of New Mexico, Albuquerque, NM, USA.

Convergence of Three Methods to Resolve Discrepant Immunoassay Digitoxin Results

We have observed significant analytical discrepancies (20% to 220%) in digitoxin (Crystodigin; DTN) immunoassay results for 11 serum samples from patients taking digitoxin. We used three methods—HPLC, immunoassay, and liquid chromatography electrospray mass spectrometry (LC/MS)—to investigate the possible sources of these discrepancies. DTN is indicated for treatment of heart failure, atrial flutter, and supraventricular tachycardia (1). This drug is the most slowly excreted cardiac glycoside, with a half-life of 4 to 10 days (2). Administration and therapeutic monitoring of DTN are more popular in European countries than in the US. Plasma concentrations of 15–25 μg/L are considered therapeutic (3), and values >35 μg/L have been associated with toxicity in 80% of patients (4). Biotransformation of DTN is complex. It is oxidatively cleaved to bisdigitoxoside (bis-DTN) in the liver, catalyzed by a specific cytochrome P-450 enzyme (5). Further deglycosylation to monodigitoxoside (mono-DTN) and digitoxigenin has been documented in mice, rabbits, and guinea pigs (5). DTN can be hydroxylated at position 12 to form digoxin. Glucuronidation of mono-DTN and, to a lesser extent, of digitoxigenin to form polar conjugates has also been documented (6). In isolated guinea pig atria, the positive inotropic actions of DTN and its metabolites have been ranked in order of decreasing activity as follows: mono-DTN, bis-DTN, digoxin, DTN, digitoxigenin (7). Discrepant patients’ samples had been analyzed by the following immunoassays: ACS:180® (Chiron Diagnostics), which utilizes a monoclonal antibody with chemiluminescence detection; TDx® (Abbott Labs.), which utilizes a polyclonal antibody and fluorescence polarization detection; and DPC (Diagnostic Products Corp.), which uses a polyclonal antibody with RIA technology. Patients’ samples had been collected in Germany in accordance with the institutional human studies regulations of that country. All immunoassays had been performed according to their manufacturers’ instructions. Initially, we expected the deglycosylated congeners of …

On-site laboratory monitoring on the intensive care unit. Blood gas, electrolyte, glucose, hemoglobin and lactate determination with the CIBA Corning 865 Analysis System

For decision-making in the ICU, rapid and accurate analysis of vital laboratory parameters is essential. The industry provides devices which analyse these parameters on a decentralised setting and which are designed for use by non-laboratory personnel. We investigated whether accuracy and handling of a new analyser (Ciba-Corning 865, Chiron Diagnostics, Medfield, USA) are good enough for basing clinical decisions on the measured parameters. The Ciba-Corning 865 allows measurement of blood gases, electrolytes, haemoglobin, glucose and lactate by use of photometric, ion-selective, enzymatic and electrochemical sensors in less than 18 microliters of whole blood. In a cardiac surgical intensive-care unit the accuracy of the device was tested by comparison to 61 measurements of quality control reagents, 48 tonometered blood samples and 536 parallel measurements in the clinical laboratory. Besides a 10-minute instruction, the participating personnel had no formal training with the device. The differences between measurements in quality control reagents and tonometered blood and the expected value were lower than 5%. The comparison with clinical laboratory measurements showed correlation coefficients from 0.94 (sodium) to 0.99 (glucose, lactate). The biases in Bland-Altman analyses were below 5%, the limits of agreement were found to be in a clinically acceptable range for all parameters. During the test period no technical problems occurred with the analyser and good acceptance by the personnel was found. The measured parameters were accurate enough to be used for therapeutic decisions in acute care medicine. Although it should not be a complete alternative to the clinical laboratory, because of rapid analyses, small sample volumes and easy handling the use of the Ciba-Corning 865 is advantageous for patients and users.

Oxaprozin and 5-(p-Hydroxyphenyl)- 5-phenylhydantoin Interference in Phenytoin Immunoassays

Rainey et al. (1) recently published their studies on metabolite and matrix interference in Abbott TDx® Phenytoin (TDx) and Phenytoin-II (TDxII) assays (Abbott Labs., Abbott Park, IL). They report that TDx Phenytoin, which uses a polyclonal antibody, demonstrates a substantial positive bias in patients with renal insufficiency because of the assay’s high (15.9%) cross-reactivity to the major metabolites of phenytoin, 5-( p -hydroxyphenyl)-5-phenylhydantoin (HPPH) and its glucuronide ester (HPPG) (2). They also report that the TDxII assay, which uses a monoclonal antibody, has high (∼50%) cross-reactivity to a nonsteroidal anti-inflammatory drug, oxaprozin (Daypro®) (1). During a recent study, a patient taking oxaprozin demonstrated discrepancy between phenytoin values by the TDxII, which gave the result in the toxic range, and that by Chiron Diagnostics’ …

Interference of oleandrin and oleandrigenin in digitoxin immunoassays: minimal cross reactivity with a new monoclonal chemiluminescent assay and high cross reactivity with the fluorescence polarization assay.

Toxicity from ingestion of the oleander plant is common. Oleandrin, the oleander glycoside, has structural similarity to cardiac glycoside digoxin and is known to cross react with various digoxin immunoassays. The authors studied the cross reactivity of oleandrin and its deglycosylated congener oleandrigenin with a fluorescence polarization immunoassay for digitoxin and compared their results with a new chemiluminescent assay for digitoxin on the Automated Chemiluminescent System (ACS:180 Plus) from Chiron Diagnostics. Even though the chemiluminescent assay has been reported to be comparable with the fluorescence polarization assay among normal patient population, oleandrin and oleandrigenin showed very high cross reactivities with the fluorescence polarization immunoassay and minimal cross reactivity with the new chemiluminescent assay. When the authors supplemented a serum specimen containing no digitoxin with 50 micrograms/ml of oleandrin, the fluorescence polarization assay recorded a value of 535.7 ng/ml of digitoxin equivalent, whereas the new chemiluminescent assay recorded a value of 10.3 ng/ml of digitoxin equivalent. The cross reactivity of oleandrigenin with the fluorescence polarization immunoassay for digitoxin was significantly lower than oleandrin. The presence of oleandrin also falsely elevated total digitoxin level in a specimen supplemented with digitoxin and oleandrin. The authors also measured free digitoxin concentration by the fluorescence polarization immunoassay in the ultrafiltrate of serum supplemented with digitoxin and oleandrin. Because digitoxin and oleandrin are bound strongly to protein, monitoring free digitoxin concentration by the fluorescence polarization immunoassay instead of total digitoxin concentration does not eliminate oleandrin interference. The authors conclude that fluorescence polarization immunoassay for digitoxin has a high cross reactivity with oleandrin and can falsely elevate digitoxin concentration in the presence of oleandrin, whereas the new chemiluminescent assay for digitoxin is almost free from interferences from oleandrin.

Ciba Corning ACS:180 Direct Total Testosterone Assay Can Be Used on Female Sera

We were intrigued by the article by Fitzgerald and Herold (1), which compared the fully automated, nonisotopic, direct (i.e., no serum purification step performed before analysis) assay of total testosterone used in the Ciba Corning Diagnostics ACS:180 instrument (Chiron Diagnostics, Medfield, MA) with a chemical ionization GC-MS method and with a manual, coated-tube, direct RIA [Coat-A-Count; Diagnostic Products Corp. (DPC), Los Angeles, CA]. The advantages of an accurate, fully automated, nonisotopic testosterone method over a manual RIA, with or without a purification step, are obvious. The authors observed excellent correlation ( r = 0.99) between testosterone values obtained with the ACS:180 vs GC-MS of male sera (1). However, the poor correlation ( r = 0.56) between testosterone values obtained with the ACS:180 vs GC-MS of female sera, prompted them to suggest “that Fuqua’s recommendation of a purification step before immunoassay analysis should be extended to include all female specimens, since ACS and DPC immunoassays did not agree with GC-MS” (1). In women, measurement of the serum testosterone concentration is useful in evaluating hirsutism, alopecia, and menstrual disorders. With assays by the ACS:180 method/instrument, hirsute women have been shown to have testosterone concentrations 0.7–1.4 times the upper limit (2.5 nmol/L) of the reference interval (2). We obtained good agreement between testosterone values quantified with the ACS:180 vs the DPC method (DPC testosterone = 0.974ACS + 0.357; r = 0.969; n = 35) used routinely in our laboratory. Because of the advantages of the fully automated ACS:180 system, we changed to this method. The recommendation by Fuqua, endorsed by Fitzgerald and Herold (1), however, prompted us … bAuthor for correspondence.

Samples from Patients to Laboratories. Walter Guder, Sheshadri Narayanan, Hermann Wisser, Bernd Zawta. Darmstadt: Git Verlag, 1996, 101 pp., 48 DM. ISBN 3–928865-22-6.

Abstract An Analytical and Clinical Comparison of ACST BR with Two Other Breast Tumor Marker Assays Houser, S.M., Maimonis, P.J. Chiron Diagnostics, East Walpole, MA