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PubMed2003

[Control of accuracy of immunoserological laboratory data on medical network and standardization].

Construction of a medical network for each region and organization has become possible by utilization of information technology. Standardization of the data on the medical network is urgent. Especially, the standardization of immunoserological data is much delayed. In this study, the possibility of standardization of such data was reconsidered based on the findings from various control surveys. Regarding the measurement items for serum concentrations of proteins and other compounds, we concluded that standardization should occur in a manner similar to the method for standardization of biochemical data and accurate control. The data on CRP, IgG, IgA, IgM and AFP, which are determined using the respective standard compound, were converged to a range with inter-facility differences of less than 10% CV. The data on CEA were also converged to achieve an inter-facility difference of less than 10% CV through repeated survey. Automatic measurement for the markers of infection diseases has progressed, and the expression of measurements was changed to the absolute value of COI, U/ml or IU/ml although it was titer in the past. Since these expressions now coexist, it is impossible to standardize the data with absolute qualitative values. It seemed necessary to present them uniformly with qualitative or clinical criteria values or express the presence or absence of infection by a combination of related markers. The measurements obtained from autoantibody-related tests using identical reagent were found coincident, but measurements obtained using different reagents were discrepant and the differences were greater than the sensitivity of measurement. In immunoserological testing and immunochemical testing, it is most important whether the antigen/antibody used as the reagent is the same preparation or not. Therefore, the test should be reconsidered through setting a certain restrictions on each recognition site of epitope and antibody. Thus, we concluded that use of a suitable standard substance is effective for standardization of immunological data.

Biomarkers↗
PubMed1992

Standards for professional service programs in audiology and speech-language pathology.

In the June/July 1991 issue of Asha, the Council on Professional Standards published for comment proposed revisions of the standards for American Speech-Language-Hearing Association (ASHA) Professional Services Board (PSB) accreditation. The council considered all of the comments received, made appropriate revisions, and took final action on the revised standards, which will become effective on January 1, 1994. The new standards and implementation statements related to each standard are provided in the following sections. The Standards represent requirements that must be met by all applicants. Implementation Statements are designed to interpret and supplement the standards by providing examples, referencing relevant policy or guideline statements, or specifying types of data or other documentation relevant to a specific standard. The implementation statements were developed by the PSB and have been reviewed by the Council on Professional Standards.

Audiology↗
PubMed2004

Electronic implementation of national nursing standards--NANDA, NOC and NIC as an effective teaching tool.

With the increased interest in evidence-based medicine, Internet access and the growing emphasis on national standards, there is an increased challenge for teaching institutions and nursing services to teach and implement standards. At the same time, electronic clinical documentation tools have started to become a common format for recording nursing notes. The major aim of this paper is to ascertain and assess the availability of clinical nursing tools based on the NANDA, NOC and NIC standards. Faculty at 20 large nursing schools and directors of nursing at 20 hospitals were interviewed regarding the use of nursing standards in clinical documentation packages, not only for teaching purposes but also for use in hospital-based systems to ensure patient safety. A survey tool was utilized that covered questions regarding what nursing standards are being taught in the nursing schools, what standards are encouraged by the hospitals, and teaching initiatives that include clinical documentation tools. Information was collected on how utilizing these standards in a clinical or hospital setting can improve the overall quality of care. Analysis included univariate and bivariate analysis. The consensus between both groups was that the NANDA, NOC and NIC national standards are the most widely taught and utilized. In addition, a training initiative was identified within a large university where a clinical documentation system based on these standards was developed utilizing handheld devices.

Interviews as Topic↗
PubMedDate not supplied

Cut-off levels based on deviation from standard negative control is better than moderate level based on fixed cut-off for ACA assessed using ELISA for the diagnosis of antiphospholipid syndrome.

AIM: To assess the consistency of the standard negative control of IgG and IgM ACA levels within runs and batches of tests, and levels of ACA agreement between those established according to deviation from standard negative control and those established based on a fixed level cut off. METHODS: Serum samples of 148 patients who presented an INR < 0.9 or prothrombin activity of > 130% or aPTT below 0.8 times control or thrombosis with aPTT below 1.2 times control were tested in a 22-time running test to determine IgG and IgM ACA levels using Quanta Lite ACA IgG (HRP) and Quanta Lite ACA IgM (HRP) commercial reagents. RESULTS: Coefficients of variant within runs and batches of standard negative control IgG and IgM ACA levels were 19.30% and 29.17% respectively. Using kappa statistics to determine degree of agreement between cut-off levels by deviation from standard negative control and fixed cut-off level of ACA identified using ELISA, the disagreement in IgM and IgG were k 0.30, and 95% CI of k 0.27 to 0.34 (z = 1.033, p = 0.3015), and k 0.63, and 95% CI of k 0.53 to 0.73 (z = 1.411, p = 0.1584) for cut-off levels based on deviations from standard negative control and fixed cut-off levels respectively. Cut-off levels based on deviation from standard negative control was more sensitive, with a 92% predictive true positive value, compared to a 69% predictive true positive value by fixed cut-off levels of IgM ACA detected using ELISA, and nearly equivalent to IgG ACA, with 84.4% and 87.1% predictive true positive values respectively. CONCLUSION: Cut-off points based on fixed levels of ACA detected using ELISA cannot be applied, because both IgG and IgM ACA levels of standard negative control were inconsistent among runs and batches. Cut-off points based on the deviation of 3 standard negative control levels for IgG ACA and based on deviations of 2.5 times from standard negative control levels for IgM ACA were better than cut off by fixed levels of ACA in producing true positive results.

Antibodies, Anticardiolipin↗
PubMed2006

[Construction of standard human transcript dataset based on RefSeq and human genome sequence database].

The NCBI Reference Sequence (RefSeq) database aimed to provide a biologically non-redundant collection of DNA, RNA, and protein sequences and to promote the research on genes and proteins of human beings and other species. However, because of widely distributed polymorphisms and different quality control of experiments in individual laboratories, there are potential problems need to be identified in the RefSeq database. Regarding which, we herein define the concept, standard transcript, based on the Central Dogmas of Biology that each standard transcript should be perfectly mapped to the standard genomic DNA sequence at the exon level. A large scale analysis for mapping all of the RefSeq records of human being (2005-4-18) to the officially released human genome sequence database (2005-4-20) was further performed using BLAT, Sim4 and a homemade program, EIparser, which was especially designed for this purpose. The standard transcripts based on the RefSeq database were obtained according to the alignment with standard human genome database. There are 9,771 RefSeq records of human being labeled with "NM_" and "NR_" could be perfectly mapped to human genome sequences, while other 10,943 records could be considered as standard transcripts after reasonable revision by comparing with the genome sequences according to all of the three methods. Moreover, the left 203 unrevisable records and 2,676 inconsistent records reported by the above programs could not be considered as standard transcripts and should be checked critically before using because of potential errors in them. Our study has thus provided a reference standard dataset of human beings with high quality for further bioinformatic and experimental analysis such as polymorphism and mutation of human genes. The reference standard dataset based on above criteria could be retrieved from http://biocompute.bmi.ac.cn/transcriptome/index.htm.

Databases, Genetic↗
PubMed2005

Result of standard patch test in patients suspected of having allergic contact dermatitis.

Contact dermatitis is a common skin disease. Disease was diagnosed by a history of contact substance together with geographic distribution of lesion. Up till now, standard patch test is one of the most reliable test to identify and confirm causative agent of allergic contact dermatitis. To determine the rate of positive standard patch test and to identify the common allergen of contact dermatitis in Thailand, we performed the standard patch test in 129 patients, suspected having allergic contact dermatitis at Department of Dermatology, King Chulalongkorn Memorial Hospital, Thailand from June 1, 2003 to September 1, 2004. The rate of positive standard patch test is 59.7% (n = 77/129). The most 3 common positive allergens were nickel sulfate (18.60%), cobalt chloride (17.05%) and fragrance mix (14.73%), respectively. The chance of positive standard patch test significantly correlated with sex (woman), initial diagnosis as contact dermatitis and history of house-worker (p = 0.017, p = 0.005 and p = 0.023, respectively). Whereas, there were no significant correlation between the chance of positive standard patch test and age of patient, location of lesion, history of recurrence, history of atopy, history of drug and food allergy. In addition, history of metal allergy significantly correlated with the chance of positive nickel sulfate or cobalt chloride in standard patch test (p = 0.017). In conclusion, this study demonstrated the prevalence of causative allergen of contact dermatitis in Thai patients using that standard patch test. Moreover, our data shown that the chance positive standard patch test was greater in patient, who were women or initial diagnosed as contact dermatitis or had history of houseworker or history of metal allergy.

Adolescent↗
PubMed1987

G-tolerance standards for aircrew training and selection.

G tolerance widely among individuals. It stands to reason that aircrew with higher G tolerance are less likely to experience symptoms of G stress in flight than are those with lower G tolerance, and that they can fly highly maneuverable aircraft with greater safety and effectiveness. To assure that aircrew with abnormally low G tolerance are not assigned to aircraft that operate in the high-G environment, a G-tolerance standard and the means to implement that standard are necessary. Since 1977, for human centrifuge operations, the USAF School of Aerospace Medicine has used an informal G-tolerance standard for selecting experimental subjects, evaluating medically disqualified aircrew, and ensuring efficacy of high-G training for aircrew. That standard consists of the subject's being able to sustain a rapidly applied +7-Gz load for 15 s, without totally losing peripheral vision or losing consciousness, while wearing a functioning anti-G suit, performing an anti-G straining maneuver, and sitting in a conventionally configured fighter aircraft seal. Inability to tolerate a 7-G, 15-s, rapid-onset G profile in a centrifuge is also the basis of internationally recognized (NATO, ASCC) definitions of low G tolerance. The rationale for choosing the 7-G, 15-s standard is discussed. Experience with use of this standard, and the equivalent standard of 8 G for 15 s when the F-16-configured seat is used, reveals that fewer than 1% of actively flying aircrew are unable to meet the standard. Eventually a formal, more stringent, G-tolerance standard may become a valuable component of the means of selecting and training aircrew for high-performance fighter aircraft.

Aerospace Medicine↗
PubMed1985

External and internal standards in the single-isotope derivative (radioenzymatic) measurement of plasma norepinephrine and epinephrine.

In plasma from normal humans (n = 9, 35 samples) and from patients with diabetes mellitus (n = 12, 24 samples) single-isotope derivative (radioenzymatic) plasma norepinephrine and epinephrine concentrations calculated from external standard curves constructed in a normal plasma pool were identical to those calculated from internal standards added to an aliquot of each plasma sample. In plasma from patients with end-stage renal failure receiving long-term dialysis (n = 34, 109 samples), competitive catechol-O-methyltransferase (COMT) inhibitory activity resulted in a systematic error when external standards in a normal plasma pool were used, as reported previously; values so calculated averaged 21% (+/- 12%, SD) lower than those calculated from internal standards. However, when external standard curves were constructed in plasma from a given patient with renal failure and used to calculate that patient's values, or in a renal failure plasma pool and used to calculate all renal failure values, norepinephrine and epinephrine concentrations were not significantly different from those calculated from internal standards. We conclude: (1) External standard curves constructed in plasma from a given patient with renal failure can be used to measure norepinephrine and epinephrine in plasma from that patient; further, external standards in a renal failure plasma pool can be used for assays in patients with end-stage renal failure receiving long-term dialysis. (2) Major COMT inhibitory activity is not present commonly if samples from patients with renal failure are excluded. Thus, it would appear that external standard curves constructed in normal plasma can be used to measure norepinephrine and epinephrine precisely in samples from persons who do not have renal failure.(ABSTRACT TRUNCATED AT 250 WORDS)

Catechol O-Methyltransferase↗
PubMed1995

[The standard of required medical responsibility as an instrument in malpractice cases].

This article is about the meaning of "standards" in medical treatment. We want to work out especially the function of "standard" as an instrument of legal requirements in medical responsibility, the forming of "standard" with real or normative criterias as well as the guidelines to the right use of standard by the judgement of medical care: 1. The "standard of necessary medical care" is a need but not a totally binding instrument to determine the required medical treatment. It marks special rules that are generally accepted by knowledge of science and practise. 2. "Standard" does not determine a special method for now and forever. It is variable and leaves space for other new methods whose expected success is not unproportional to the risks. The danger of standardization can be the establishing of backwards directed previous methods. 3. A fundamental instrument of establishing "standard" as a judicial criteria are the medical experts. They have the difficult role of mediator between medical methods and judicial responsibility according to the standard of necessary medical care.

Clinical Competence↗
PubMed1996

Rapid placement of transpyloric feeding tubes: a comparison of pH-assisted and standard insertion techniques in children.

OBJECTIVE: To compare transpyloric feeding tube placement using a pH-assisted placement technique versus a standard placement technique in pediatric patients requiring enteral nutrition. METHODS: Critically ill children younger than 4 years were prospectively and randomly assigned to either a pH-assisted or a standard feeding tube placement group. Identical pH-assisted feeding tubes were used in both groups; however, feeding tubes in the standard group were not attached to a portable pH meter. Successful transpyloric placement was confirmed by radiography before beginning feedings. If placement was not successful, a second placement attempt was made after metoclopramide administration. Information regarding tube placement success, number of radiographs, time to initiation of feedings, and daily caloric intake was collected. A cost comparison between the two groups was performed. RESULTS: Thirty-four patients were enrolled in the pH-assisted group, and 34 were enrolled in the standard feeding tube group. Ninety-seven percent of patients in the pH-assisted group had successful placement after the first attempt, compared with 53% of patients in the standard group. The average time to successful placement of pH-assisted feeding tubes was 6 minutes. All patients in the pH-assisted group had successful placement after the second attempt, compared with 78% of patients in the standard group. A pH of greater than 5.6 accurately predicted transpyloric placement in 97% (33 of 34) of individuals in the pH-assisted group. Children in the pH-assisted group required significantly fewer radiographs than those in the standard group. Hospital costs were $114 per patient in the pH-assisted group and $135 per patient in the standard group. CONCLUSIONS: Our findings indicate that bedside transpyloric placement of pH-assisted feeding tubes can be accomplished rapidly and with a high success rate. This method is associated with decreased radiation exposure and economic savings when compared with a standard placement technique.

Child, Preschool↗
PubMed1996

Stimulation of cytokine production via a special standardized mistletoe preparation in an in vitro human skin bioassay.

The mistletoe preparation Lektinol is standardized with respect to bioactive mistletoe lectin, the active component of mistletoe. This standardized mistletoe preparation and its active components (mistletoe lectins) were compared in the skin2 bioassay in vitro for their capacity to stimulate interleukin 1 alpha and interleukin 6 release from skin analogue tissue, composed of human cells in their naturally secreted matrix. The standardized mistletoe preparation, its basic ingredient, aqueous mistletoe extract, and pure mistletoe lectins all stimulated IL-1 alpha and IL-6 release from skin2 tissues during 24 h incubation. The amounts of cytokines released from various skin2 tissue lots by mistletoe lectin I (ML I) (0.75-8.0 ng/ml) and by the standardized mistletoe preparation remained relatively constant across a series of different batches. Concentration-response curves to the standardized mistletoe preparation and ML I were similar for IL-1 alpha and IL-6 release. The importance of the concentration of mistletoe lectins for the cytokine-releasing action of the standardized mistletoe preparation was confirmed using a neutralizing anti-mistletoe lectin antiserum. CONCLUSIONS. Using the skin2 method it was shown that reproducible stimulation of cytokine release by a standardized mistletoe preparation from batch to batch is one of the notable features of its pharmaceutical quality. This standardized mistletoe preparation therefore represents a preparation with constant immunobiological effects. Mistletoe lectins of the standardized mistletoe preparation are the active substances in the skin2 bioassay. The skin2 method is a reliable quantitative bioassay for determination of immunopharmacological effects.

Biological Assay↗
PubMed1996

[Study on the test and evaluation of the toxicity of the strains preparation of the different subspecies of Bacillus thuringiensis and on the research into its standardization].

In this paper using the preparation of Bacillus thuringiensis of USA standard sample-subsp. kurstaki HD-1-S-1980 (H3a3b) the toxicity to different subspecies preparations such as subsp. dendrolimus U strain(H4a4b), subsp. galleriae C88 strain (H5a5b) is tested and evaluated. And product's standardization is also researched. Comparing their toxicity to various test-insects between the standard sample prepared from U strain and USA, standard sample, the boilogical determined results are as follows: the toxicity of U strain standard sample is respectively 18666.6 IU/mg(test-insects: Dendrolimus punctatus, 2nd larva), 22956.5 IU/mg(test-insects: Plutella kylostella, 2nd larva). The above-mentioned toxicity evaluations are higher than that of 16000 IU/mg of USA standard sample. The comparison in susceptibility shows as follows: suscepticibility of plutella kylostella is stronger than that of Dendrolimus punctatus. The products from U strain and C88 strain are trial-produced in medium-scale. The product's toxicity to test-insect Dendrolimus punctatus is determined using USA standard sample. The results are obtained as follows the toxicity evaluation of U strain products is 36444.4 IU/mg; that of C88 strain products is 28521.7 IU/mg. The both are obviously higher than that of USA standard sample. This proves that different subspecies strain's toxicity to the same test-insect is with defference and it is an important way to raise product's toxicity by improving and optimizing process in production. The whole experiment shows it is feasible to rectify the evaluation of the toxicity of our country's present products using USA standard sample, Dendrolimus punctatus and Plutella kylostella as test-insets. And it is simple and convienient as well as save time and save effort to make statistical analysis in computer with Basic program. To do statistical and operational analysis using our designed basic programming by micro-computer is more accurate and repid than by caculator.

Animals↗
PubMed1997

Path test reactions to the Chinese Standard Screening Allergens in 1,135 patients investigated for allergic contact dermatitis.

BACKGROUND: The patch test has become the standard method of investigating patients with allergic contact dermatitis. Many countries have developed standard screening allergens to make patch testing more efficient. A series of the Chinese Standard Screening Allergens were studied and modified. OBJECTIVE: This study investigated the frequency of contact allergies in suspected allergic contact dermatitis and tested the practicality of the Chinese Standard Screening Patch Test Allergens. METHODS: A total of 1,135 patients suspected of having allergic contact dermatitis were patch tested. Three hundred twelve (27.5%) were men, and their age ranged from 2 to 75 years old (mean age, 34.3 years), 823 (72.5%) were women, and their age ranged from 2 to 76 years old (mean age, 33.0 years). Nanjing Medical University supplied the Chinese Standard Screening Allergens and Finn-Chamber. All patients were patch tested according to the Chinese Standard Screening Patch Test Allergens with Finn-Chamber the protocol as established by the International Contact Dermatitis Research Group (ICDRG). RESULTS: From the 1,135 patients suspected to have allergic contact dermatitis, 650 (57.3%) had at least one positive reaction. Nineteen (95%) of the Chinese Standard Screening Patch Test Allergens had positive reactions higher than 1%. Of 485 patients with negative reaction to the Standard Allergens, 106 patients were tested with other suspected contactants according to history. Thirty-nine (36.8%) had positive reactions to the contactants they provided. The total positive rate therefore increased by 3.4%. CONCLUSIONS: Our study results indicate that the Chinese Standard Screening Patch Test Allergens are suitable for use in routine clinic in China.

Adolescent↗
PubMed1997

[The standardization of medical care and the training of medical personnel].

The medical specialist training at all levels (medical orderly, doctor's assistant, general practitioner, doctors) should be based on the medical care standards. Preliminary studies in the field of military medicine standards have demonstrated that the medical service of the Armed Forces of Russia needs medical resources' standards, structure and organization standards, technology standards. Military medical service resources' standards should reflect the requisitions for: all medical specialists' qualification, equipment and material for medical set-ups, field medical systems, drugs, etc. Standards for structures and organization should include requisitions for: command and control systems in military formations' and task forces' medical services and their information support; health-care and evacuation functions, sanitary control and anti-epidemic measures and personnel health protection. Technology standards development could improve and regulate the health care procedures in the process of evacuation. Standards' development will help to solve the problem of the data-base for the military medicine education system and medical research.

First Aid↗
PubMed2006

Comparing MR image intensity standardization against tissue characterizability of magnetization transfer ratio imaging.

PURPOSE: To evaluate existing methods of standardization by exploiting the well-known tissue characterizing property of magnetization transfer ratio (MTR) values obtained from MT imaging, and compare the tissue characterizability of standardized T2, proton density (PD), and T1 images against the MTR images. MATERIALS AND METHODS: Image intensity standardization is a postprocessing method that was designed to correct for acquisition-to-acquisition signal intensity variations (nonstandardness) inherent in magnetic resonance (MR) images. The main idea of this technique is to deform the volume image histogram of each study to match a standard histogram, and to utilize the resulting transformations to map the image intensities into a standard scale. The method has been shown to produce a significant gain in similarity of resulting images and to achieve numeric tissue characterization. In this work we compared PD-, T2-, and T1-weighted images before and after standardization with the corresponding MT images for 10 patient MRI studies of the brain, in terms of the normalized median values on the corresponding image histograms. RESULTS: No statistically significant difference was observed between the standardized PD-, T2-, and T1-weighted images and the corresponding MTR images. However, a statistically significant difference was found between the pre- and poststandardized PD-, T2-, and T1-weighted images, and between the prestandardized PD-, T2-, and T1-weighted images and the corresponding MTR images. CONCLUSION: These results suggest that standardized T2, PD, and T1 images and their tissue-specific intensity signatures may be useful for characterizing disease.

Brain↗
PubMed2004

Quantitation of drug metabolites in the absence of pure metabolite standards by high-performance liquid chromatography coupled with a chemiluminescence nitrogen detector and mass spectrometer.

Quantitative information on drug metabolites with pharmacological or toxicological activities is of great interest during the drug discovery and development process. Because the analyte response with mass spectrometry can change significantly due to small variations in chemical structure, pure standards are required to construct standard curves for quantitation. However, for most programs at the discovery stage, pure metabolite standards are not available. In this work, an evaluation was conducted using a chemiluminescent nitrogen detector (CLND) as a calibrator to obtain the response factor ratio on a mass spectrometer generated from a metabolite and its parent compound in biological fluids. Using the response factor ratio obtained from the CLND, the metabolite could be quantified with the liquid chromatography/tandem mass spectrometry (LC/MS/MS) response obtained from the parent drug's standard curve. For this evaluation, oxazepam and temazepam were chosen as a 'drug/metabolite' pair. Temazepam was treated as the methylated metabolite of oxazepam. A spiked dog urine sample with a known concentration of oxazepam and unknown concentration of temazepam was injected onto the HPLC system and detected by both the CLND and MS/MS. Taking advantage of the equimolar response feature of the CLND, a response factor ratio between temazepam and oxazepam on the mass spectrometer was obtained by comparing the peak areas generated on the CLND and the mass spectrometer. From this ratio, temazepam was quantified using the oxazepam standard curve. The difference between the concentration of temazepam obtained from the reconstructed standard curve and the concentration obtained directly from a real temazepam standard curve was within 13% except the least concentrated standard (31%). This methodology has been successfully applied to measure quantities of the metabolite of a proprietary compound in a dog pharmacokinetic (PK) study.

Animals↗
PubMed2006

Assessing the properties of internal standards for quantitative matrix-assisted laser desorption/ionization mass spectrometry of small molecules.

Growing interest in the ability to conduct quantitative assays for small molecules by matrix-assisted laser desorption/ionization (MALDI) has been the driving force for several recent studies. This present work includes the investigation of internal standards for these analyses using a high-repetition rate MALDI triple quadrupole instrument. Certain physicochemical properties are assessed for predicting possible matches for internal standards for different small molecules. The importance of similar molecular weight of an internal standard to its analyte is seen through experiments with a series of acylcarnitines, having a fixed charge site and growing alkyl chain length. Both acetyl- and hexanoyl-carnitine were systematically assessed with several other acylcarnitine compounds as internal standards. The results clearly demonstrate that closely matched molecular weights between analyte and internal standard are essential for acceptable quantitation results. Using alpha-cyano-4-hydroxycinnamic acid as the organic matrix, the similarities between analyte and internal standard remain the most important parameter and not necessarily their even distribution within the solid sample spot. Several 4-quinolone antibiotics as well as a diverse group of pharmaceutical drugs were tested as internal standards for the 4-quinolone, ciprofloxacin. Quantitative results were shown using the solution-phase properties, log D and pKa, of these molecules. Their distribution coefficients, log D, are demonstrated as a fundamental parameter for similar crystallization patterns of analyte and internal standard. In the end, it was also possible to quantify ciprofloxacin using a drug from a different compound class, namely quinidine, having a similar log D value as the analyte.

Carnitine↗
PubMed1995

Preparation and characterization of RNA standards for use in quantitative branched DNA hybridization assays.

RNA standards were developed for use in quantitative hybridization assays such as the Quantiplex HCV RNA Assay and Quantiplex HIV RNA Assay, which are based on branched DNA signal amplification. In vitro transcripts ranging in size from 0.5 to 9.4 kb were prepared and purified by phenol extraction following gel electrophoresis or column chromatography. Aliquots of the transcripts were digested to nucleosides and phosphate and then quantified by phosphate analysis against the U.S. National Institute of Standards and Technology phosphate standard. The quantitation was checked by OD260 and by either hyperchromicity or isotopic tracer analysis. The quantitation of each lot of RNA agreed within 20% by the three methods. The reproducibility of the methods was tested by preparing a total of 13 lots of standard RNAs. The average percentage full-length RNA of the 13 lots was 82%, with a range of 59 to 97%. The standard RNAs were used to test the ability of the branched DNA hybridization assay to quantify all target RNAs accurately regardless of size or slight variations in sequence. Standard Hepatitis C virus (HCV) RNAs of 1.3, 2.2, and 3.2 kb showed that size has no detectable effect on quantitation in the branched DNA hybridization assay. Three different lots of standard 3.2-kb HCV RNA were serially diluted and quantified over a thousand-fold range in the branched DNA hybridization assay. The average signal per attomole of target varied by less than 20% among the 3 lots. Standard HCV RNA transcripts were also prepared from clones of HCV subtypes 1b and 3a to study the effects of target sequence diversity and probe design on quantitation by hybridization.(ABSTRACT TRUNCATED AT 250 WORDS)

Base Sequence↗