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Results for “Repeatability and Reproducibility”

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PubMed1999

Determination of clenbuterol residues in bovine hair by using diphasic dialysis and gas chromatography-mass spectrometry.

A method for the determination of clenbuterol (4-amino-3,5-dichloro-alpha[(tert.-butylamino)methyl]-benzyl alcohol hydrochloride) in hair of living cows has been developed. Hair samples were digested in an alkaline medium. The diphasic dialysis technique is a semi-permeable membrane technology developed for the direct extraction of relatively low-molecular-mass analytes such as clenbuterol. In this case, we used sodium citrate buffer to homogenize the digested hair, dichloromethane was used as the extraction solvent at 37 degrees C, and stirring was applied at 150 rpm for 4 h. The analysis was carried out using gas chromatography-mass spectrometry. The calibration curve for clenbuterol in hair was linear in the range from 12.5 to 400 ng g(-1). The detection limit of clenbuterol was 5 ng g(-1) and the quantification limit was 12.5 ng g(-1), in hair. A good inter-day reproducibility was obtained (R.S.D. = 7.08%). The repeatability and intra-day reproducibility (50 ng g(-1) of hair, n = 10) show R.S.D.s of 7.1 and 9.5%, respectively.

Animals↗

PubMed1999

Reproducibility of the oxygen uptake efficiency slope in normal healthy subjects.

BACKGROUND: To elucidate the intertest agreement of the oxygen uptake efficiency slope (OUES) in comparison with those of the maximal oxygen uptake (VO2max) and the ventilatory anaerobic threshold (VAT). METHODS EXPERIMENTAL DESIGN: A comparative study. SETTING: Institutional practice. A total of 19 healthy volunteers underwent two sessions of maximal exercise testing with an interval of no more than 7 days. The testing was conducted on a cycle ergometer with the work rate increased by either 20, 30, or 40 Watts (W)/min so that the subject would reach exhaustion within 9 to 12 min of exercise. VAT was defined as the level of oxygen uptake (VO2) at which either an increase in the ventilatory equivalent for oxygen without a concomitant increase in the ventilatory equivalent for carbon dioxide or a change in the slope of the linear relationship between carbon-dioxide production (VCO2) and VO2 occurred. OUES was determined by the following equation: VO2 = a log VE + b, where VE was minute ventilation and "a" was the OUES. Intertest reproducibility was assessed by coefficient of repeatability (COR). RESULTS: The intertest reproducibility of VO2max and OUES were excellent (COR = 570 ml/min [16%] and 740 [20%], respectively). VAT showed poor agreement between the two tests (COR = 650 ml/min [31%]). CONCLUSIONS: Results show that OUES is reproducible and reliable, supporting the clinical usefulness of this index.

Adult↗

PubMed1999

[Reproducible marginal gap measurements of partial ceramic crowns].

Aim of this research was to test the hypothesis that marginal gap measurements by a digital microscopic image processing computer are reproducible. Light microscopic images of the margins of Artglass partial crowns on stone dies were obtained with a 3CCD color video camera, digitized and processed. Ten measuring points were painted on a 0.5 mm section of the finish line of the preparation. The opposite corresponding measuring points on the margin of the partial crown were painted as well. The distance (marginal gap) between two corresponding points was painted and calculated by the computer. Reproducibility (precision) is reflected in the ability to reproduce the same measurement results in repeated measurements (n = 5). The reproducibility error was expressed as the coefficient of variation (CV) in percent (%). The localization of the corresponding measurement points and the calculation of the marginal gap were performed without errors. For a marginal gap between 15-50 microns the average measurement error was 3% or 0.45-1.5 microns. It was concluded that the measurement of the gap between two points by the digital image processing computer was reproducible. The measurement error was neglectable given that a clinically acceptable marginal gap is 100 microns.

Ceramics↗

PubMed1998

The potential of restricted access media columns as applied in coupled-column LC/LC-TSP/MS/MS for the high-speed determination of target compounds in serum. Application to the direct trace analysis of salbutamol and clenbuterol.

This study investigated the potential of restricted access media (RAM) columns used as a first column in coupled-column LC hyphenated to thermospray tandem mass spectrometry (LC/LC-TSP/MS/MS) for the fast, selective, and sensitive determination of target drugs in serum samples. Because of their wide range in polarity, salbutamol and clenbuterol were chosen as model compounds and representatives of the class of beta 2-agonists. Three types of RAM columns were tested: (i) Pinkerton ISRP (internal surface reversed phase, 5 microns), (ii) SPS (semipermeable surface, 5 microns C18), and (iii) RP-18 ADS (alkyl-diol silica, 25 microns). A 3-micron C18 column (50 mm x 4.6 mm i.d.) was chosen as the second column. Tandem mass spectrometric detection was carried out in the selected reaction monitoring (one parent-->one daughter) mode. With regard to retention and, moreover, the peak elution volume of the analytes, the ISRP material was found to perform best: a 50-mm x 4.6-mm i.d. ISRP column in combination with a 100% aqueous buffer (pH of 7.0 +/- 0.2) allowed the injection of large volumes (up to 200 microL) of sample without additional band broadening of the analytes and provided sufficient preseparation between analytes and large-molecule serum constituents. Under the selected conditions, both analytes could be determined in serum samples up to a limit of quantification (LOQ) of 0.5 ng/mL, with a sample throughput of 7 and 5 h-1 for salbutamol and clenbuterol, respectively. Method validation was carried out by analyzing, in the course of several days, calf and human serum samples spiked with the analytes. In the case of salbutamol, the overall recovery from serum samples spiked at levels between 0.5 and 50 ppb (n = 33) was 103.4%, with a repeatability of 12.7% and reproducibility of 14.3%. The overall recovery for clenbuterol was 99.6% (n = 15, spiked level 0.5-5 ppb), with a repeatability of 15.2% and reproducibility of 16.4%. The adopted LC/LC-TSP/MS/ MS analyzer appeared to be very robust under the selected conditions, and, after the period of analysis involving the processing of more than 100 mL of serum, neither loss of chromatographic performance nor pressure increase of columns or of the interface was observed.

Adrenergic beta-Agonists↗

PubMed1986

Continuous 24 hour intragastric pH monitoring: focus on reproducibility in duodenal ulcer patients. A preliminary report.

Continuous 24 h intragastric pH monitoring is increasingly recommended for deciding which is the most appropriate regimen and dosage of new gastric antisecretory drugs. In order to assess its reproducibility, we have repeated the test twice on consecutive days in six patients with endoscopically proven duodenal ulcers because this type of patient seems to be the most suitable for studies on the efficacy of the above mentioned therapy. No patient received medication during the two examination days. Our data showed there was no significant difference (t = 0.31, p = 0.76) between the 24 h areas under the curve of pH profiles of the first day compared with those of the second (mean +/- SD : 3.152 +/- 681 vs 3.073 +/- 1,122). The lack of significant difference (p = 0.20) between the mean times elapsed at the various pH levels during the first and second days was further proof of the reproducibility of the method. As wells these results suggest that day-to-day reproducibility of the technique is good in duodenal ulcer patients. Therefore, its repeated use on the same patient to investigate the effects of various drugs and their different dosages on gastric acidity appears to be reliable.

Adult↗

PubMed1995

The reproducibility of depressive and hypomanic symptoms across repeated episodes in patients with rapid-cycling bipolar disorder.

The purpose of this study is to determine the stability of symptoms of hypomania and depression across repeated affective episodes in patients with rapid-cycling bipolar disorder. Nine patients had a total of 30 depressive episodes and 31 hypomanic episodes during the period of observation. Standardized observer ratings indicated that the three symptoms most consistently reported during depressive episodes were fatiguability, decreased work activities and hypersomnia. These results as well as those from the standardized observer ratings of hypomania indicate that depression in this population consists of a lethargic, hypoactive state while hypomania may be a heightened state of activation. The clinical and theoretical implications of these findings are discussed.

Adult↗

PubMed1987

Helical repeat of DNA in solution. The V curve method.

The V-like dependence of the electrophoretic mobility of small DNA rings on their topological constraint, which has been documented in a recent paper [Zivanovic et al. (1986), J. Mol. Biol., 192, 645-660], has been explored as a tool to measure the helical twist of the torsionally unstressed duplex. The method was applied to single mixed sequence fragments approximately 350 to 1400 base pairs in length, providing estimates of their average helical periodicity. It was also used to compare two DNA fragments, and to evaluate the helical repeat of poly(dA.dT).poly(dA.dT) and poly(dA).poly(dT) inserts, and the helix unwindings associated with dA and dC methylations by dam and Hhal methylases, respectively. Data were found to be highly reproducible and helical repeat estimates were in good agreement with those obtained from previous techniques.

DNA, Bacterial↗

PubMed2004

Measurement reproducibility in the early stages of biomarker development.

Biomarker discovery and development requires measurement reproducibility studies in addition to case-control studies. Parallel pursuit of reproducibility studies is especially important for emerging technologies such as protein biomarkers based on time-of-flight mass spectrometry, the case considered in this paper. For parallel studies, a way to improve reproducibility prior to identification of protein species is necessary. One approach is use of functional principal components analysis (PCA) as the basis for assessing measurement reproducibility. Reproducibility studies involve repeated measurement of a reference material such as a human serum standard. Measurement in our example is by SELDI-TOF (surface-enhanced laser desorption and ionization time-of-flight) mass spectrometry. Reproducibility is defined in reference to a source of variation, which in our example is associated with a type of commercially available protein biochip. We obtained spectra for 8 spots on each 11 chips. Two spectra are generally more alike when obtained from the same chip rather than different chips. Thus, our experiment indicates potential improvements from reducing variation in chip manufacture and chip handling during measurement. Our analysis involves careful registration of the spectra and characterization of the spectral differences. As shown by our example, a metrological analysis may enhance case-control studies by guiding optimization of the measurements underlying the biomarker.

Biomarkers↗

PubMed1997

Measurements of vision function and quality of life in patients with cataracts in southern India. Report of instrument development.

OBJECTIVE: To develop and validate vision function (VF) and quality of life (QOL) instruments in patients with cataracts in the context of large volume surgery in a developing country. MATERIALS AND METHODS: The instruments were developed using a consensus approach. One hundred patients who were undergoing cataract surgery at Aravind Eye Hospital, Madurai, India, were interviewed preoperatively and 3 and 12 months postoperatively. Standard clinical procedures were followed, including measurement of visual acuity. Between-interviewer reproducibility was measured by repeated administration of the preoperative questionnaire. Within-interviewer reproducibility was measured preoperatively in a separate study of 50 patients. RESULTS: Preoperative scores from the VF and QOL instruments were significantly associated with visual acuity (r = 0.4). Internal reliability (Cronbach alpha) was greater than .9. Both instruments showed large changes after surgery, with effect sizes of 3 or greater for most VF scales (range, 1.8-3.7) and 1 or greater for QOL scales (range, 1.0-2.2). Changes in visual acuity after surgery were correlated with changes in the VF (r = 0.44) and QOL (r = 0.41) scale scores. Between-interviewer reproducibility was acceptable (total VF scale, Spearman r = 0.7; total QOL scale; r = 0.74). The kappa values were lower for within-interviewer reproducibility. CONCLUSIONS: The study provided strong evidence for the validity, reproducibility, and responsiveness of the instruments, and for the feasibility of using them in the setting of a large volume of cataract surgery in a developing country.

Cataract↗

PubMed2006

Elevation of glucocorticoids is necessary but not sufficient for the escalation of cocaine self-administration by chronic electric footshock stress in rats.

The examination of cocaine self-administration (SA) by rats under conditions that promote escalating patterns of intake should lead to a better understanding of factors that contribute to cocaine addiction. This study investigated the ability of repeated daily exposure to a stressor, electric footshock (EFS), to escalate cocaine SA. Male Sprague-Dawley rats were trained to self-administer cocaine (0.5 mg/kg/inf, i.v.) by pressing a lever under a FR4 schedule during 2-h sessions comprised of four 30-min SA components. Repeated daily EFS consisting of shock sequences (3 x 0.6 mA, 100-ms duration, 1-s frequency) delivered under a variable time 45-s schedule for 5 min before each of the four SA components across 14 days of SA testing produced a significant escalation of cocaine SA. EFS failed to escalate food-reinforced lever pressing and did not alter cocaine SA when administered either inside or outside of the SA context 4 h after daily SA testing. Surgical adrenalectomy along with diurnal corticosterone (CORT) replacement prevented EFS-induced escalation without altering SA in the absence of EFS, indicating that increases in circulating glucocorticoids were necessary for the escalating effects of EFS. Elevation of CORT through repeated daily CORT injections (3.0 mg/kg, i.p.) failed to reproduce the effects of repeated daily EFS on SA, but restored the escalating effects of EFS in adrenalectomized rats with CORT replacement, suggesting that an elevation of glucocorticoids was necessary but alone was not sufficient for the escalation of cocaine SA by EFS.

Animals↗

PubMed2003

Validation of EN ISO standard methods 6888 Part 1 and Part 2: 1999--enumeration of coagulase-positive staphylococci in foods.

The methods of European and International Organisations for Standardization for the enumeration of coagulase-positive staphylococci (CPS, Staphylococcus aureus and other species) described in EN ISO 6888 Part 1 and Part 2: 1999 were validated by order of the European Commission (Standards, Measurement and Testing Fourth Framework Programme Project SMT4-CT96-2098). EN ISO 6888-1 prescribes the use of Baird-Parker (BP) agar whereas EN ISO 6888-2 prescribes the use of Rabbit Plasma Fibrinogen Agar (RPFA). The objective was to determine the precision of each method in terms of repeatability (r) and reproducibility (R) using three different food types inoculated with various levels of S. aureus and a typical background flora. The results are intended for publication in the associated standards. Cheese, meat and dried egg powder were examined by 24 laboratories from 16 countries in Europe. Each participant received eight test materials per food type: blind duplicates at four inoculum levels (0, 10(3), 10(4) to 10(5), 10(5) to 10(6) cfu/g). In addition, two reference materials (RM) (capsules containing milk powder inoculated with S. aureus) were included in the study. All test materials were subjected to stringent homogeneity and stability testing before being used in the collaborative trial. Two statistical methods were used to calculate the precision parameters. Draft EN ISO 16140: 2000 method appeared more appropriate to the case of microbiological data than ISO 5725-2: 1994 method and was retained to calculate the precision data. Concerning EN ISO 6888-1, overall values for repeatability (r) when used with food test materials was r=log(10) 0.28 (expressed as an absolute difference between log(10)-transformed test results). For the reference materials, r=log(10) 0.19. Overall values for reproducibility (R) when used with food test materials were R=log(10) 0.43. For the reference materials, R=log(10) 0.39. Concerning EN ISO 6888-2, overall values for repeatability (r) when used with food test materials were r=log(10) 0.22. For the reference materials, r=log(10) 0.17. Overall values for reproducibility (R) when used with food test materials were R=log(10) 0.33. For the reference materials, R=log(10) 0.31. These results were presented to the ISO technical committee and to the Comité Européen de Normalisation (CEN). Both committees agreed to incorporate the precision data obtained with food materials as two amendments to EN ISO 6888-1 and -2, and to give an equal status to each part of the standard.

Bacteriological Techniques↗

PubMed1999

Differences in reproducibility and peak growth hormone responses to repeated testing with various stimulators in healthy adults.

In healthy adults, GH responses to provocative testing are variable between subjects. Information on the intra-subject variability is limited, despite the importance attached to GH stimulation tests in the diagnosis of GH deficiency. We have investigated and compared the variability of different GH stimulation tests in a group of healthy control subjects. In 16 healthy non-obese adults, two insulin tolerance tests (ITT) (0.15 IU/kg body weight i.v. and a fall in blood glucose < or = 2.2 mmol/l) two GHRH tests (1 microgram/kg body weight i.v.), and two clonidine (CLO) (300 micrograms p.o.) + GHRH (60 min later) tests were performed in the morning after an overnight fast. A pyridostigmine (PD) (120 mg p.o. 60 min before GHRH) + GHRH test was performed twice in an extended group of 31 healthy adult subjects. A wide range of GH responses was observed. Both during the ITT and the GHRH test, low values in the range generally recognized to reflect impairment of GH secretory status were encountered. The median (range) peak GH responses in tests 1 and 2 were: (a) ITT: 14.4 micrograms/l (4.1-71.1) and 14.0 micrograms/l (0.09-69.5), (b) GHRH test: 21.7 micrograms/l (0.71-56.2) and 18.4 micrograms/l (1.6-55.1); (c) CLO + GHRH test: 57.4 micrograms/l (22.9-209) and 65.8 micrograms/l (12.2-206); (d) PD + GHRH test: 36.5 micrograms/l (9.1-125) and 44.6 micrograms/l (6.3-101). The coefficients of variation (CV) were: 58% (ITT), 45% (GHRH), 46% (CLO + GHRH) and 26% (PD + GHRH). The peak GH responses were significantly different in all tests (CLO + GHRH > PD + GHRH > GHRH > ITT). In the individual subject, there was no systematic correlation between the peak GH responses in the different stimulation tests. In conclusion, we found that the stimulated GH responses were highly variable in all tests, and that the peak GH responses differed. Test results in patients should be evaluated against test-specific reference values, and caution is justified in the interpretation of low responses in a single test.

Adult↗

PubMed1997

Determination of urea kinetics by isotope dilution with [13C]urea and gas chromatography-isotope ratio mass spectrometry (GC-IRMS) analysis.

1. Stable urea isotopes can be used to study urea kinetics in humans. The use of stable urea isotopes for studying urea kinetic parameters in humans on a large scale is hampered by the high costs of the labelled material. We devised a urea dilution for measurement of the distribution volume, production rate and clearance of urea in healthy subjects and renal failure patients using the inexpensive single labelled [13C]urea isotope with subsequent analysis by headspace chromatography-isotope ratio MS (GC-IRMS) of the [13C]urea enrichment. 2. The method involves measurement of the molar percentage excess of [13C]urea in plasma samples taken over a 4 h period after an intravenous bolus injection of [13C]urea. During the sample processing procedure, the plasma samples together with calibration samples containing a known molar percentage excess of [13C]urea are acidified with phosphoric acid to remove endogenous CO2, and are subsequently incubated with urease to convert the urea present in the plasma samples into CO2. The 13C enrichment of the generated CO2 is analysed by means of GC-IRMS. This method allows measurement of the molar percentage excess of [13C]urea to an accuracy of 0.02%. 3. Reproducibility studies showed that the sample processing procedure [within-run coefficient of variation (CV) < 2.8% and between-run CV < 8.8%] and the GC-IRMS analysis (within-day CV < 1.3% and between-day CV < 1.3%) could be repeated with good reproducibility. 4. In clinical urea kinetic studies in a healthy subject and in a renal failure patient without residual renal function, reproducible values of the distribution volume, production rate and clearance of urea were determined using minimal amounts of [13C]urea (25-50 mg). 5. Because only low [13C]urea enrichments are needed in this urea dilution method using GC-IRMS analysis, the costs of urea kinetic studies are reduced considerably, especially in patients with renal failure.

Adult↗

PubMed1999

Rapid determination of glyphosate in cereal samples by means of pre-column derivatisation with 9-fluorenylmethyl chloroformate and coupled-column liquid chromatography with fluorescence detection.

A rapid procedure for the determination of glyphosate in cereals has been developed. Convenient sample pretreatment is carried out by (i) a overnight standing extraction of 1.0 g homogenized sample with 20 ml of water, (ii) centrifugation of the samples, (iii) a passing of 2.5 ml of the clear layer through a 100 mg C18 solid-phase extraction cartridge and (iv) collection of the last 1.5 ml of the eluent into a calibrated tube. For the instrumental analysis, the efficient approach developed earlier for environmental water samples [J.V. Sancho, F. Hernández, F.J. LUpez, E.A. Hogendoorn, E. Dijkman, P. van Zoonen, J. Chromatogr. A, 737 (1996) 75] was successfully adopted for the determination of glyphosate in the obtained cereal extracts. The procedure includes a 15 min derivatisation step of the analyte with 9-fluorenylmethyl chloroformate and a 16 times dilution step prior to instrumental analysis employing coupled-column LC with fluorescence detection. The developed procedure has a sample throughput of more than 25 samples per day and a limit of quantification of 0.5 mg/kg. The method was validated by analyzing freshly spiked cereal samples and samples with aged residues at levels between 1.0 and 10 mg/kg. The overall recovery of the freshly spiked samples was 86% (n = 10) with a repeatability of 6.5% and a reproducibility of 9.5%. For samples with aged residues recoveries performed at different time intervals (range 80-150 days) did not differ significantly; the overall recovery (n = 10) was 74% with a repeatability and reproducibility of 14 and 20%, respectively.

Chromatography, High Pressure Liquid↗

PubMed2000

Repeated quantitative perfusion and contrast permeability measurement in the MRI examination of a CNS tumor.

This study reports on the results of quantitative MRI perfusion and contrast permeability measurement on two occasions in one patient. The measurements were separated 81 days in time. The tumor grew considerably in this period, but no change was found with respect to perfusion and contrast permeability. Non-involved white matter values were reproduced to demonstrate repeatability. The presented approach to dynamic susceptibility contrast MRI allows fast and repeatable quantitative assessment of perfusion and is easily integrated in a conventional brain tumor protocol.

Adult↗

PubMed1996

HLA-DPA1 typing by PCR amplification with sequence-specific primers (PCR-SSP) and distribution of DPA1 alleles in Caucasian, African and Oriental populations.

In the present study PCR primers were designed for detecting all known DPA1 variability, i.e., the presently recognized six DPA1 alleles 0103 to 0401, and also for separation of the four DPA1*02 alleles, by PCR amplification with sequence-specific primers (PCR-SSP). For each sample seven different PCR reactions were performed which allowed the identification of all DPA1 alleles and the resolution of all DPA1 genotypes. Forty-eight cell lines and 100 donor spleen cells were investigated by the DPA1 PCR-SSP technique. In the forty-eight known workshop cell-lines no false positive or false negative results were obtained. The 100 donor spleen cells were only typed by the PCR-SSP technique and in their DNAs only one or two DPA1 alleles were found. Twenty cell lines and twenty donor spleen cells were typed on two separate occasions and interpreted blindly. The reproducibility between the repeated typings was 100%. The length of the specific products ranged from 103 to 258 base pairs and the amplification patterns obtained were easy to interpret. In conclusion, DPA1 typing by the PCR-SSP method is an accurate typing technique with high sensitivity, specificity and reproducibility. Analysis of the distribution of DPA1 alleles was performed in 100 Caucasian samples, 100 African samples and 80 Oriental samples, including separation of the four of HLA-DPA1 alleles. Each ethnic group appeared to have one (Caucasians), or two (Africans and Orientals), frequent DPA1 allele(s) and a high frequency of DPA1 homozygotes, suggesting that, like for the DPB1 locus, balancing selection does not appear to be affecting the evolution of the DPA1 locus.

Alleles↗

PubMed1984

Site of deposition and factors affecting clearance of aerosolized solute from canine lungs.

We determined the influence of several factors on lung solute clearance using aerosolized 99mTc-diethylenetriaminepentaacetate. We used a jet nebulizer-plate separator-balloon system to generate particles with an activity median aerodynamic diameter of 1.1 micron, administered the aerosol in a standard fashion, and determined clearance half times (t1/2) with a gamma-scintillation camera. The following serial studies were performed in five anesthetized, paralyzed, intubated, mechanically ventilated dogs: 1) control, with ventilatory frequency (f) = 15 breaths/min and tidal volume (VT) = 15 ml/kg during solute clearance; 2) repeat control, for reproducibility; 3) increased frequency, with f = 25 breaths/min and VT = 10 ml/kg; 4) positive end-expiratory pressure (PEEP) of 10 cmH2O; 5) unilateral pulmonary arterial occlusion (PAO); and 6) bronchial arterial occlusion (BAO). Control t1/2 was 25 +/- 5 min and did not change in the repeat control, increased frequency, or BAO experiments. PEEP markedly decreased t1/2 to 13 +/- 3 min (P less than 0.01), and PAO increased it to 37 +/- 6 min (P less than 0.05). We conclude that clearance from the lungs by our method is uninfluenced by increased frequency, increases markedly with PEEP, and depends on pulmonary, not bronchial, blood flow.

Aerosols↗

PubMed2003

Immune profiling of plasma and cervical secretions using recycling immunoaffinity chromatography.

Small volumes of cervical secretions have limited measurements of immunity at the cervix, which may be important to studies of human papillomavirus (HPV). We report the use of recycling immunoaffinity chromatography to efficiently study immune profiles in cervical secretions. Frozen pairs of plasma and cervical secretions (collected on ophthalmic sponges) were selected randomly from women with normal cervical cytology (n = 50) participating in a natural history study of HPV in Guanacaste, Costa Rica. Single 25- micro l aliquots of plasma and (diluted) cervical secretions were assayed for interleukin (IL) -1 beta, -2, -4, -6, -8, -10, -12, -13, -15, IFN-alpha, -beta, -gamma, tumor necrosis factor-alpha, -beta, RANTES (regulated on activation normal T-cell express and secreted), MCP-1 (monocyte chemoattractant protein), -2, -3, macrophage inflammatory protein-1 alpha, -1 beta (regulated on activation normal T-cell express and secreted), macrophage colony-stimulating factor, IgG, IgA, and cyclooxygenase 2. All of the specimens were tested as blind replicates, and refrozen plasma was retested 4 months later. To evaluate the reproducibility of the repeat measurements and to examine the correlation between plasma and cervical secretions, we calculated kappa values with 95% confidence intervals among categorized analyte values and Spearman correlation coefficients (rho) among detectable, continuous analyte values. Measurements of all of the analytes in either plasma or cervical secretions were highly reproducible, with all of the kappa > or = 0.78 (70% above 0.90), and all of the rho > or = 0.88 (96% above 0.90). Only IL-1 beta (kappa = 0.60 and rho = 0.82) and IL-6 (kappa = 0.50 and rho = 0.78) levels were strongly correlated between plasma and cervical secretions. IFN-gamma, tumor necrosis factor-beta, RANTES, MCP-1, MCP -2, macrophage inflammatory protein-1 alpha, and macrophage colony-stimulating factor levels were especially poorly correlated between plasma and cervical secretions (kappa < or = 0.25 and rho < or = 0.25). We conclude that recycling immunoaffinity chromatography is a reproducible method of measuring immune profiles from biological specimens, and immune profiles are not well correlated between plasma and cervical secretions, perhaps necessitating cervical collections to study cervix-specific immunity in HPV natural history studies.

Adult↗