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T A Grooms

Publications and source records attributed to T A Grooms.

8 recordsLinked to original sources
PubMed1986

Interlaboratory testing of the transferability of a candidate reference method for total cholesterol in serum.

In 1975 the Centers for Disease Control, in cooperation with the American Association for Clinical Chemistry Cholesterol Reference Method Study Group, began an investigation to develop a reference method for total cholesterol. Five potential reference methods were compared with the definitive method developed by the National Bureau of Standards before the chemical method of Abell et al. (J Biol Chem 1952;195:357-66) was selected as the recommended reference method. Because acceptance of a proposed reference method depends so greatly on the method's capability for transfer to other laboratories by written specifications and instructions, a transferability testing study was designed and conducted with 14 laboratories. The study consisted of preliminary testing of readiness of equipment, reagents, and personnel followed by transferability testing with eight runs on 10 serum pools. Laboratoires that did not meet readiness specifications had higher CVs in the transferability testing. The study demonstrated that the proposed method permits laboratories to attain a CV of less than 1.5% for one laboratory and of less than 3.0% among laboratories. The mean percent bias value was less than 1.0% for six of the 14 laboratories, less than 1.5% for 12, and less than 3.0% for all 14 laboratories.

Calibration↗
PubMed1984

Rapid electroenzymatic measurement of lactate in microsamples of spinal fluid.

A lactate sensor, which makes possible rapid direct measurement of L-lactate in small samples of spinal fluid, has been developed. This enzyme electrode gives a linear current output as a function of hydrogen peroxide generated by a lactate oxygen oxidoreductase sandwiched between two membranes. The membranes serve to support the oxidase, prevent the diffusion of soluble electroactive species such as urate, ascorbate, and phenolic drugs such as acetaminophen, and to form a diffusion-limited path for the lactate. A 10 or 25 microL sample of spinal fluid is injected into a 350 microL thermostated chamber containing a suitable buffer and the electrode's sensing surface. The method has been tested by analysis of spinal fluid, with amounts of lactate up to 15 mmol/L, by comparison with a photoenzymatic method. A correlation coefficient of 0.999 was found. With a new cellulose ester membrane, acetaminophen levels up to 10 mmol/L did not interfere. A YSI glucose analyzer can be converted to a lactate analyzer by changing the O-ring mounted enzyme transducer membrane.

Electrodes↗
PubMed1984

Rapid micromeasurement of lactate in whole blood.

A new lactate sensor makes it possible to measure the lactate content of whole blood directly in less than 1 min, using only a 10-microL blood sample. The procedure works equally well with plasma, serum, spinal fluid, other body fluids, or tissue homogenates. The instrument is calibrated with lactate standards between 0 and 15 mMol/L. The sensor, a polarographic enzyme electrode, gives a current which is a linear function of the lactate concentration. There is no interference from glucose, pyruvate, alcohol, ascorbate, anticoagulants, lidocaine, acetaminophen, or other drugs and metabolites commonly encountered in critically ill patients. The lactate sensor is composed of a peroxide sensor and an enzyme transducer membrane. The lactate is stoichiometrically converted to pyruvate and hydrogen peroxide by lactate oxygen oxidoreductase derived from Pediococcus species. The oxygen required for the enzymatic oxidation is supplied via an air-permeable silicone elastomeric membrane used for stirring. Comparison of our new electroenzymatic method with the Boehringer-Mannheim photoenzymatic method gives correlations of 0.997 for both whole blood and plasma.

Alcohol Oxidoreductases↗
PubMed1981

One-minute electrochemical enzymic assay for cholesterol in biological materials.

In this rapid and specific micro-scale electrochemical enzymic assay for cholesterol and cholesterol esters, 10 microL of standard or sample is injected directly into a heated (50 degrees C) thermostated, oxystated cuvet containing pH 7.25 buffer, cholesterol oxidase (EC 1.1.3.6), and cholesterol esterase (EC 3.1.1.13). The cholesterol esters are hydrolyzed by the esterase, and the cholesterol is simultaneously oxidized by the oxidase. The hydrogen peroxide produced from oxidation of the unesterified cholesterol is measured by a polarographic anode covered with an acetate/polycarbonate membrane. The membrane allows hydrogen peroxide to diffuse to the platinum anode, where it is oxidized, but prevents the diffusion of ascorbic acid, uric acid, and bilirubin to the electroactive surface. Turbidity does not interfere. The correlation (r) between results by our method and the Abell-Kendall method for 105 samples of serum was 0.9994 and for 105 samples of plasma was 0.9997. Our method is convenient for the analysis of high-density lipoprotein cholesterol in plasma and serum supernates and in many kinds of tissue homogenates. Its limitations are also described.

Cholesterol↗