Development of the Logical Observation Identifier Names and Codes (LOINC) vocabulary

The LOINC (Logical Observation Identifier Names and Codes) vocabulary is a set of more than 10,000 names and codes developed for use as observation identifiers in standardized messages exchanged between clinical computer systems. The goal of the study was to create universal names and codes for clinical observations that could be used by all clinical information systems. The LOINC names are structured to facilitate rapid matching, either automated or manual, between local vocabularies and the universal LOINC codes. If LOINC codes are used in clinical messages, each system participating in data exchange needs to match its local vocabulary to the standard vocabulary only once. This will reduce both the time and cost of implementing standardized interfaces. The history of the development of the LOINC vocabulary and the methodology used in its creation are described.

Logical observation identifier names and codes (LOINC) database: a public use set of codes and names for electronic reporting of clinical laboratory test results

Many laboratories use electronic message standards to transmit results to their clients. If all laboratories used the same "universal" set of test identifiers, electronic transmission of results would be greatly simplified. The Logical Observation Identifier Names and Codes (LOINC) database aims to be such a code system, covering at least 98% of the average laboratory's tests. The LOINC database should be of interest to hospitals, clinical laboratories, doctors' offices, state health departments, governmental healthcare providers, third-party payors, organizations involved in clinical trials, and quality assurance and utilization reviewers. The fifth release of the LOINC database, containing codes, names, and synonyms for approximately 6300 test observations, is now available on the Internet for public use. Here we describe the LOINC database, the methods used to produce it, and how it may be obtained.

Logical observation identifier names and codes (LOINC) database: a public use set of codes and names for electronic reporting of clinical laboratory test results

Many laboratories use electronic message standards to transmit results to their clients. If all laboratories used the same "universal" set of test identifiers, electronic transmission of results would be greatly simplified. The Logical Observation Identifier Names and Codes (LOINC) database aims to be such a code system, covering at least 98% of the average laboratory's tests. The LOINC database should be of interest to hospitals, clinical laboratories, doctors' offices, state health departments, governmental healthcare providers, third-party payors, organizations involved in clinical trials, and quality assurance and utilization reviewers. The fifth release of the LOINC database, containing codes, names, and synonyms for approximately 6300 test observations, is now available on the Internet for public use. Here we describe the LOINC database, the methods used to produce it, and how it may be obtained.

Medical nomenclature and common conventions for trauma registries

A trauma registry has been created containing lexicons of terms arranged to foster the adoption of standardized and extensible terminology for the nature and mode of injury. Identification of attribute sets for the nature-of-injury (body region:detailed part:type of injury) and for the mode-of-injury (mechanism:agent:activity:intent:setting) allows the assembly of a clear, concise, easily usable, nad extensible format for representing the appropriate level of detail for nomenclature or classification. This ability allows the use of a common list of terms that is adaptable for case records used in patient care as well as in trauma registry statistics. Several examples of reports using these attributes are shown.

Implementation of attractive dialogues in nutritive analysis and clinical dietetics information systems

The implementation and evaluation of a system providing both extensive nutritive-analysis calculations and interactive capabilities are described. The extensive calculating ability of the system arose from the historic need for nutrient intake estimates in clinical investigation and nutritional research. The availability of computer-aided instruction (CAI) system software lead to adoption of the interactive style originating at Ohio State University. Capabilities evolved into an extended interactive processor utilizing an extensive data-base. The interactive processor functions either directly, for immediate response, or as a preprocessor for the more extensive processing system. Use of this capability by a dietetics consortium in the Pacific North-west has lead to definitions of effective and desirable styles of interaction by dietitians with a food and nutrient data-base. Hosting the PILOT CAI language with a high-level language, SAIL, allowed convenient and flexible dialogue creation as well as computational power. The central data-base was restructured on two occasions to accommodate the required characteristics for foods and their nutrients. The lack of interfaces between medical-information packages, and between languages, presently limits the growth of this system into a fully integrated component of the health-care information domain.

Information and clinical pharmacology: role of the computer

The author notes the need for information from a variety of sources in order to support decision processes of the clinical pharmacologist. One of the data-bases urgently required is a central collection of drug information, which includes quantitative pharmacokinetic data as well as qualitative data and which would be used in evaluating complex drug interactions as well as uncomplicated adverse reactions. The need to be able to link these data-bases with others is noted. The need to develop professional consensus on data-base structure algorithms and the lexicon and terms used to create such systems is discussed. The role of the various professional societies is suggested with the observation that examples of this kind of effort and an awareness of the need for its existence are on hand.

Human factor IX in animals: kinetics from isolated, radiolabelled protein and platelet destruction following crude concentrate infusions

Crude, concentrated and isolated, labelled human factor IX was prepared and infused into animals. Initially, two dogs with severe haemophilia B received both preparations and factor IX clotting activity and label survived well. Kinetic parameters fit a two-compartment open model. For 12 infusions of concentrates into normal baboons, clotting and antigen data again fit the model. Similar kinetics, with less variability, were found for nine infusions of [125I]factor IX. Radioactivity of the first post-infusion samples was > 90% precipitated in the double antibody system with an average of 84% of counts adsorbable to barium citrate. Compared to plasma, barium adsorbable counts gave a shorter t1/2 beta-elimination phase suggesting a small recirculating 125iodide pool. When [125I]factor IX was rechromatographed over heparin-agarose, variable amounts of altered, labelled protein were present; this species was more rapidly cleared from plasma post-infusion. Twelve infusions of crude concentrates into baboons were given to animals whose platelets had been labelled with 51Cr. Platelet counts as well as survival were then followed. For seven of these animals, mean counts decreased and the labelled platelets were destroyed, to an average of 21%, during the first 4 h post-infusion. Subsequent platelet survival was normal. Three infusions of gel-filtered, crude concentrates and two infusions of 'activated' commercial concentrates did not significantly alter platelet survival.

Pharmacokinetics of amikacin in patients with normal or impaired renal function: radioenzymatic acetylation assay

The acetylating radioenzymatic assay was used for determination of levels of amikacin in serum and urine. Because of an inhibitor present in various amounts in urine, assay of amikacin in urine by this method requires added internal standards and thus is less precise than the assay in serum. Determination of the rate of plasma clearance, half-life, and volume of distribution of amikacin in 10 patients with normal renal function, four patients undergoing dialysis, and five patients with end-stage renal diseases have shown a relation of half-life (t1/2 in hr) to rate of clearance of serum creatinine (Cer) of t1/2 = 3 X Cer, the same relation as found for kanamycin and gentamicin. The apparent steady-state volume of distribution of amikacin in patients with diminished renal function is slightly, but not significantly, larger than that in normal patients; the values were 0.28 +/- 0.10 and 0.21 +/- 0.10, respectively. In normal patients, 87% of the drug is excreted by the kidney.

Assay of flucytosine and furosemide by high-pressure liquid chromatography

A high-pressure liquid chromatographic method for the analysis of flucytosine and furosemide concentrations in biological fluid is described. The separations were carried out on a pellicular cation-exchange resin eluted with an ammonium phosphate buffer. Detection of elution peaks was by UV absorption at 280 nm and fluorescence monitoring. Advantages of the method are specificity, minimal preanalysis sample workup, and small sample size.

Furosemide Concentrations in Serum and Urine, and Its Binding by Serum Proteins as Measured Fluorometrically

We describe a modification of the fluorometric method of Häussler and Hajdú [Arzneim. Forsch. 14, 704 and 709 (1964)] for assay of furosemide in either serum or urine. A 1-ml sample, acidified to pH 2, is extracted with 5 ml of diethyl ether; 4 ml of the ether is back-extracted into 1 ml of phosphate buffer (pH 7.0, 0.1 mol/liter), and finally acidified with 1 ml of dilute HCl (0.6 mol/liter). A procedure for estimating blanks in urine was derived to correct for dilution caused by diuresis. Internal standards are used, and the "effective" extraction ratio is used to correct for the effects of quenching and extraction differences. In equilibrium, 93% of the drug is bound to serum proteins; 65% is tightly bound. Erythrocytes contain less than 5% of the drug. Quantum yield of fluorescence at pH 1 is 0.0496 for furosemide and is 0.0163 for 4-chloro-5-sulfamoylanthranilic acid. Furosemide fluorescence diminishes with increasing pH, while that of 4-chloro-5-sulfamoylanthranilic acid (a degradation product) increases.

Vasopressor-induced natriuresis and altered intrarenal haemodynamics in cirrhotic man

1. The influence of two intravenous vasopressors (angiotensin II and norepinephrine) on renal function and intrarenal blood flow distribution was studied in thirteen cirrhotic subjects and the results compared with those from eight non-cirrhotics.

2. Increased sodium excretion occurred in four of eight cirrhotics with ascites who received comparable pressor doses of angiotensin II and one of five similar subjects who received norepinephrine. In contrast, sodium excretion fell or remained the same in all eight non-cirrhotics.

3. Renal plasma flow fell and filtration fraction rose in nearly all subjects who did not respond to vasopressors with a natriuresis but changed little in those who did.

4. Vasopressor-induced changes of the multicompartmental 133xenon washout curve were qualitatively different in the group who responded with a natriuresis in comparison to the others. Whereas the distribution of flow to the fastest component fell in the non-responder, it remained the same or rose in those who developed a natriuresis.

5. We interpret these results as suggesting a state of relative renal vasopressor resistance allowing the induced systemic hypertension to reduce tubular sodium reabsorption in some cirrhotics by influencing peritubular ‘physical factors’.