Discrepancies in measurement of aspartate aminotransferase by continuous-flow analysis.

Abstract I compared results for aspartate aminotransferase (EC 2.6.1.1) obtained with a reaction-rate analyzer (LKB 2086 Mark Two), based on IFCC methodology, and a continuous-flow analyzer (the Technicon SMA 2) for 115 patients' sera and seven commercial quality-control sera. The data from the SMA 2 showed a clear positive bias in those sera with activities exceeding 40 U/L (the upper limit of the reference range). Independent data to support the bias of the SMA 2 and other continuous-flow analyzer systems are presented. Application of a correction factor to the SMA 2 data above the upper limit of the range significantly decreased this bias. Failure to apply such a factor to data obtained from continuous-flow analyzers could lead to serious clinical misinterpretation.

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Liquid and lyophilized quality-control materials compared for use in continuous-flow analysis.

Clinical Chemistry ◽

10.1093/clinchem/30.1.129 ◽

1984 ◽

Vol 30 (1) ◽

pp. 129-131 ◽

Cited By ~ 4

Author(s):

R J Elin ◽

B A Gray

Keyword(s):

Quality Control ◽

Continuous Flow ◽

Flow Analysis ◽

Quality Control Material ◽

Omnibus Test ◽

Control Material ◽

Incomplete Mixing ◽

Continuous Flow Analysis ◽

Level 3 ◽

Quality Control Materials

Abstract Using a Technicon SMAC continuous-flow instrument, we compared a liquid quality-control material ("Decision level 3," Beckman) with two different lyophilized quality-control materials. The variances for 19 analytes in the three materials were significantly greater for Decision than for the Ortho Abnormal and the Omega II lyophilized control sera (p less than 0.00001 for each comparison by the omnibus test). The imprecision for Decision was not due to incomplete mixing or carryover. The viscosity of Decision, however, was more than twice that of the two lyophilized control sera or of pooled human serum.

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Reaction Rate Measurement of Multiple Enzyme Samples by Continuous Flow Analysis

Clinical Chemistry ◽

10.1093/clinchem/13.10.847 ◽

1967 ◽

Vol 13 (10) ◽

pp. 847-854 ◽

Cited By ~ 6

Author(s):

Harold H Brown ◽

Mary R Ebner

Keyword(s):

Alkaline Phosphatase ◽

Light Absorption ◽

Continuous Flow ◽

Reaction Rate ◽

Single Point ◽

Flow Analysis ◽

Enzyme Assays ◽

Rate Measurement ◽

Kinetic Assay ◽

Continuous Flow Analysis

Abstract A simple technic to adapt the advantages of continuous flow analysis to the kinetic assay of multiple enzyme samples is described. It will permit adequate standardization by primary or secondary standards run through the entire analysis of those procedures that do not exhibit spontaneous changes in light absorption or fluorescence with time. The adaptation of the Kind-King method for alkaline phosphatase (1) to this technic is given to demonstrate the superiority of such a system over single-point enzyme assays.

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A Bubble-gating Flow Cell for Continuous-flow Analysis

Clinical Chemistry ◽

10.1093/clinchem/15.11.1045 ◽

1969 ◽

Vol 15 (11) ◽

pp. 1045-1055 ◽

Cited By ~ 15

Author(s):

R L Habig ◽

B W Schlein ◽

L Walters ◽

R E Thiers

Keyword(s):

Continuous Flow ◽

Reaction Rate ◽

Sampling Rate ◽

Flow Analysis ◽

Flow Cell ◽

Air Bubbles ◽

Readout System ◽

Protein Determination ◽

Continuous Flow Analysis ◽

Rate Method

Abstract A system is described which permits measurements, such as photometry, to be made on air-segmented streams, as in continuous-flow analysis. Elimination of the "debubbler" step before measurement provides two basic assets: (1) more rapid attainment of steady-state conditions (lower interaction between samples), and (2) maintenance of the integrity of the bubbled analysis stream, permitting subsequent handling and remeasurement. A device has been developed for detecting air bubbles. When placed across the light path of a photometer flow cell it inactivates the readout system when bubbles pass by. The resulting system measures the transmittance of each individual liquid segment of the analysis stream, while maintaining the integrity of the stream. Two examples of possible applications of this system are described. One is a simple total-protein determination with biuret, at three times the conventional sampling rate. The other is a continuous-flow, two-point, reaction-rate method for assay of alkaline phosphatase activity.

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