C.L. Jacklyn

Curve prediction in automated analyses in routine laboratories

1. The hydraulics of first- and second-generation AutoAnalyzers introduce lag and exponential deformations of the square wave signal expected from the colorimeter. These factors limit sampling rates by causing sample interaction. Curve regeneration carried out on Technicon Flame IV modules, using a digital approach, with a Hewlett-Packard 2100A computer, has successfully compensated for exponential deformation of sodium, potassium, chloride and carbon dioxide channels in routine laboratory use for one year. A sampling rate of 138/hr has been used; faster rates are possible. 2. Reduced sample and reagent consumption are benefits in addition to the increased analysis rate.

Comparison of serum sodium and chloride results for Flame IV-Auto Analyzer II, SMAC, Ektachem 400, and Nova 4 clinical analyzer systems.

We determined serum Na+ and Cl- results using Technicons Flame IV-Auto Analyzer II (FLIV/AAII) system and Kodaks Ektachem 400 clinical analyzer. Our objective was to determine whether Na+ and Cl- results from these analyzers were sufficiently similar to report to clinicians without reference to the system used for the determination. Method precision of the two systems for Na+ results was comparable; whereas Ektachem 400 Cl- results were more imprecise than those determined using the FLIV/AAII, Ektachem Na+ results showed lower correlation with the FLIV/AAII (r = 0.890) and Cl- results were more highly correlated (r = 0.960). When Kodaks newly developed equi-transferant electrolyte reference fluid (ETRF) was used with generation 4 Na+ slides and generation 1 Cl- slides the largest difference observed was 7.0 mmol/L for both Na+ and Cl- results. Using Kodak calibrators and the manufacturers operational conditions for the Ektachem 400, we observed that a considerable number of sample results for both Na+ and Cl- did not agree within 3.0 mmol/L of the FLIV/AAII values. To corroborate our finding, we also analyzed serum Na+ and Cl- using a Technicon Sequential Multiple Analyzer + Computer (SMAC) system and a Nova 4 + 4 Clinical Analyzer (Nova). We conclude that flame emission systems and direct ion specific electrode systems do not yield comparable Na+ and Cl- results even when total protein and triglyceride concentrations of the samples are within reference ranges.(ABSTRACT TRUNCATED AT 250 WORDS)

Continuous-flow enzymic determination of serum total and high density lipoprotein cholesterol using microlitre sample volumes

We determine serum total cholesterol and high-density lipoprotein cholesterol (HDL-C) using a modified Technicon Auto Analyzer II-BMC enzymic system. The method uses 25 microL of sample (serum or supernate) for cholesterol determinations. Pooled serum which was calibrated indirectly against CDCs Abell-Kendall method was used for standardization. Accuracy and precision for total cholesterol determinations are comparable to those obtained using a modified Technicon AAII method. Coefficients of variation for the determination of HDL-C prepared by heparin/Mn++ precipitation are 6.4% and 4.6% at concentration levels of 0.70 mmol/L and 0.94 mmol/L respectively. The interchangeable use of deionized-distilled water and 0.15 mol/L NaCl solution for dilution of samples analyzed by the micro method is shown to produce significantly different cholesterol estimates. The reduced reagent volumes significantly lower the cost of cholesterol determinations. The system is simple, inexpensive and yields reliable cholesterol and HDL-C results.

A comparison of serum electrolyte results by technicon's flame III and flame IV autoanalyser systems

A comparison of Technicons (Technicon, Tarrytown, N. Y., 10591) Flame III and Flame IV electrolyte Auto-Analyzer systems for the determination of Na+, K+, Cl- and CO2 in serum is described. Results from the Flame IV are determined over three periods of time and compared to those of the referee Flame III system. The Optional Digital Printer and Linearizer Modules are not used with the described system. The Flame IV AutoAnalyzer is calibrated with a multi-point calibration technique (aqueous reference standards) rather than the single-point calibration technique (albumin reference material) used by the AutoAnalyzer II. Results for the Flame IV are shown to be comparable with those for the Flame III.

Continuous-flow enzymatic determination of high-density lipoprotein cholesterol

A simple, sensitive, and precise continuous-flow (Technicon Auto Analyser II) method using enzymic reagents to measure high-density lipoprotein (HDL) cholesterol in the supernatant of serum treated with heparin-manganese reagent is described. 1. The sensitivity of the system was improved by increasing the flow rates of both sample and re-sample manifold lines to 0.23 ml/min. This allowed a recorder full-scale deflection equivalent to 840 mg cholesterol per litre, and permitted a precise determination of cholesterol in the 200-600 mg/l range. 2. Interaction between Mn++ and the enyzmic reagents caused false elevations of the peak plateau on the chart readings, especially when 2M MnCl2 was used. Addition of disodium ethylene-diaminetetra acetate (8 mmol/L) to the enzyme reagent eliminated the spike-like interference in the recorder tracings, and permitted more accurate chart readings. 3. The heparin-Mn++ reagents contributed to the measured HDL-cholesterol. Use of a saline blank improved precision. 4. The inter-assay variation was determined by analysing (n = 26) 2 quality control serum pools: X1 = 362 +/- 11.5 mg/l (CV = 3.18%) and X2 = 252 +/- 14.4 mg/l (CV = 5.74%).

Application of curve regeneration to the determination of electrolytes by the Flame IV Auto-Analyser using a mini-computer.

Curve regeneration is applied to the continuous-flow determination of serum Na +, K +, Cl- and CO2 by the Flame photometer IV (Technicon Corp.). A Hewlett-Packard 2100 A mini-computer is used for data acquisition. The continuous-flow parameters of both rise and fall curves are estimated from computer sampled voltage outputs over the standard profile. An additional interaction correction variable designated as Beta (beta) is described and applied to the regenerated peaks of the cresol red CO2 procedure. The phenolphthlalein CO2 methodology, showing improved flow parameters over those for the cresol red procedure is adapted for the Flame IV system. The basic program design is briefly outlined. Typical computer determined calibration curves (linear regression) and sample peak tracings for both the basic and regenerated techniques are illustrated.