Quantitative determination of faecal fat, nitrogen and water by means of a spectrophotometric technique: near infrared reflectance analysis (NIRA). Assessment of its accuracy and reproducibility compared with chemical methods

doi:10.1016/0009-8981(94)05993-3

Clinica Chimica Acta

Volume 234, Issues 1–2, 31 January 1995, Pages 147-156

https://doi.org/10.1016/0009-8981(94)05993-3 Get rights and content

Abstract

Measurement in faeces of the principal nutrients, fat (F), water (W) and nitrogen (N) is useful to assess digestive and absorptive functions and thus to monitor patients' progress and response to therapy in malabsorption/maldigestion syndromes. Presently available techniques are not ideal in clinical practice for serial analyses as they are time-consuming and require unpleasant and prolonged handling of the stools. The present study aimed to evaluate the accuracy and precision of near infrared reflectance analysis (NIRA) in routine measurement of fat, nitrogen and water faecal contents compared with Van de Kamer (VDK), Kjeldahl (KJ) and gravimetric-by-lyophilization (LY) methods, respectively. Fat, nitroge n and water (n = 34), were measured in the 1-day faecal collections of 15 healthy subjects and 19 patients (10, coeliac disease; 6, chronic pancreatitis; 3, small-bowel Crohn's disease). A highly significant linear correlation was found between VDK, KJ, LY methods and NIRA analysis. Very low values of intra-assay coefficient of variation indicated a remarkable analytical precision of NIRA. A recovery test at different concentrations in the useful range was performed for all three nutrients, to assess the accuracy of NIRA. Quantitative recoveries were between 95 and 105%. Data from the present study show that NIRA analysis is reproducible, accurate and rapid (less than 1 min). These characteristics make NIRA serial analysis useful in clinical practice to monitor progress and response to therapy in patients with malabsorption/maldigestion syndromes.

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Therefore, for difficult but highly valued species such as yellowtail kingfish the development of more reliable methods is required. Technologies such as NIR have become part of the nutritional arsenal of most aquafeed manufacturers and use of this technology may prove to be more cost-effective, rapid and reliable than traditional in-vivo studies, if and when suitable raw material data bases can be constructed for specific species (Aufrère et al., 1996; Boval et al., 2004; Cozzolino et al., 2002; Decruyenaere et al., 2009; Picarelli et al., 1995). Alternative in-vitro methods that more accurately simulate the digestive processes of fish also offer some advantages over traditional in-vivo techniques.
When conducting digestibility experiments with fish many researchers encounter problems that result in erroneous digestibility coefficients. Erroneous digestibility coefficients result from variability in the raw data which is amplified by the formulae used to calculate them. Variation can stem from natural differences in the digestibility of the same diet between individuals or groups of fish. It can also creep insidiously into studies due to poor preparation and mixing of ingredients or problems with the collection of faecal material or the veracity of analytical results. Therefore, it is fairly common to expect variability in data collected from digestibility trials with fish. But what can be done about it? In this paper, we present an experiment with yellowtail kingfish (Seriola lalandi) that was done to determine whether the digestibility of extruded wheat (EW) was affected by its inclusion rate (10, 20, 30 or 40% diet^− 1). The experiment, based on the indicator–ratio method, was conducted without incident, but the raw data on the nutrient and marker concentration of faecal samples was variable. We dealt with this problem by using linear regression to estimate more reliable analytical values for faecal samples. These values were used to recalculate logical digestibility coefficients for EW. Using this approach, we show that dry matter (≈ 57%–40%), carbohydrate (≈ 48%–27%) and gross energy (57–42%) digestibility of EW decline as its inclusion rate rises, whereas the digestibility of protein (≈ 84%) and the digestibility of fat (≈ 94%), remain reasonably constant. We validated the regression approach applied to yellowtail kingfish by examining published data from a similar digestibility experiment on Australian snapper Pagrus auratus. A regression approach was useful in reducing the variability in our raw data because the design of our experiment approximated a dose-response relationship. Designing digestibility experiments using a dose-response approach may prove useful in overcoming the inherent variability often encountered in these types of experiments.
Diagnosis of exocrine pancreatic insufficiency in chronic pancreatitis: <sup>13</sup>C-Mixed Triglyceride Breath Test versus Fecal Elastase
2017, Pancreatology
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To measure steatorrhea, we used NIRA instead of the classical Van de Kamer (titrimetric) method. NIRA has proved to be a reliable method for measuring fecal fat excretion [40,41]. We conclude that the present study shows that FE-1 and the TGBT have similar accuracy in the diagnosis of EPI in patients with CP.
Pancreatic enzyme replacement therapy (PERT) is indicated in case of clinically relevant exocrine pancreatic insufficiency (EPI). Clinical trials addressing PERT have used the coefficient of fat absorption (CFA) to define EPI but this test is cumbersome to perform. Our aim was to compare two easier-to-perform tests to detect clinically relevant EPI: Fecal Elastase-1 (FE-1) and ¹³C-Mixed Triglyceride Breath Test (TGBT).
We prospectively included 54 patients with chronic pancreatitis (CP), 24.1% operated, 29.6% had EPI. EPI was defined as a CFA <93%. The sensitivity (Se), specificity (Sp), positive (PPV) and negative (NPV) predictive values for different cut-offs of FE-1 and TGBT were calculated.
The area under the ROC curve for FE-1/TGBT was 0.861/0.876 for the global sample, 0.842/0.794 for non-operated patients and 0.917/1 for operated patients respectively. Se, Sp, PPV and NPV for a cut-off of FE-1 <200 μg/g were 93.8%, 63.2%, 51.7% and 96% respectively. The best cut-off point for FE-1 was 84 μg/g, which yielded an 87.5% Se, 81.6% Sp, 66.7% PPV and 93.9% NPV. The same parameters for a TGBT <29% were 81.3%, 84.2%, 68.4% and 91.4% respectively. The best cut-off point for TGBT was <23%, which yielded an 81.3% Se, 94.7% Sp, 86.7% PPV and 92.3% NPV. Diabetes was associated to decreased FE-1 levels, even in multivariate analysis.
FE-1 and TGBT showed similar results for the diagnosis of EPI in CP. In non-operated CP patients, TGBT does not offer any advantage to FE-1 but in operated CP patients TGBT seems a more accurate test.
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El objetivo del trabajo ha sido evaluar la seguridad del PEG 3350 con electrolitos (PEG + E) a nivel renal y digestivo. Objetivo secundario: valorar su eficacia y dosis de efectividad.
Quince pacientes con estreñimiento funcional (criterios de Roma III) y función renal normal fueron evaluados. La mediana de edad fue de 6,2 años (r = 2-9). Sobres pediátricos de PEG + E fueron administrados durante 4 semanas (4ST) La dosis media administrada fue de 0,44 g/kg/día. La natruria y osmolaridad urinaria se midieron al inicio y a las 4ST. La determinación de principios inmediatos en heces mediante FENIR (análisis de reflexión de infrarrojos) y una prueba de hidrógeno espirado fueron efectuadas a las 4ST. La eficacia del tratamiento fue evaluada mediante el cambio en el número de deposiciones por semana y la consistencia de las heces (escala de Bristol)
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Polyethylene glycol 3350 plus electrolytes (PEG + E) efficacy has been validated in some studies, but not many have evaluated its safety in children. The aim of our study was to evaluate the safety; renal, malabsorption or excessive production of gas and efficacy of PEG + E treatment in our paediatric population.
Fifteen patients who suffered functional constipation (Rome III criteria) were evaluated. Median age was 6.2 years (r 2-9). All patients had normal renal function. PEG + E were administered for 4 weeks (4WP). The mean dose was 0.44 g/kg/day, titrated according to age, weight and response. Urine screens (sodium and osmolality) were performed at the beginning and 4WP. Stool sample NIRA (near-infrared reflectance analysis) and hydrogen breath test analysis samples were performed at 4WP. To analyse the efficacy of the treatment, the number of stools per week and stool form type (Bristol stool scale) were recorded.
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Estudiar la validez y fiabilidad de la versión española del cuestionario revisado de calidad de vida para fibrosis quística (FQ) en adolescentes y adultos (CFQR 14+ Spain).
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El cuestionario CFQR 14+ Spain es válido y fiable para su aplicación en España, aunque podría ser mejorado en algunas de las subescalas.
The aim of this study was to assess the validity and reliability of the Spanish version of the revised disease-specific health related quality of life questionnaire for adolescents and adults with cystic fibrosis (CFQR 14+ Spain).
A total of 43 cystic fibrosis (CF) patients completed the CFQR 14+ Spain. Forced expiratory volume in 1 second, in percentage of predicted - FEV₁ (%)-, number of respiratory exacerbations, 6-minute walk test, Bhalla score (based on computerized tomography of the chest), fat-free mass index, body mass index (BMI), faecal fat and St George's Respiratory Questionnaire were included as measurements of health status.
Ten out of the twelve scales had alpha coefficients above 0.70. Test–retest correlations (Spearman) ranged from 0.49 to 0.95 and they were significant in all scales. Intraclass correlations ranged from 0.47 to 0.95 (ten out of the twelve scales were >0.70) forty out of the fifty ítems have correlations between items and scale above 0.70. All the CFQR+14 scales, except the digestive symptoms scale, discriminated significantly between patients with mild, moderate and severe disease (according to FEV₁ (%)). Other respiratory parameters also discriminated significantly between patients with mild-moderate and severe disease. Only some scales discriminated significantly between nourished and malnourished patients. All of the scales met standards for floor effects (<15% of the responders with the lowest score) but not for ceiling effects (only five out of the twelve).
The Spanish CFQR14+ (Spain) is a reliable and valid instrument for measuring the health-related quality of life in Spanish adolescents and adults with CF, though with the exception of a few of its subscales.
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2010, Sleisenger and Fordtran’s Gastrointestinal and Liver Disease- 2 Volume Set: Pathophysiology, Diagnosis, Management, Expert Consult Premium Edition - Enhanced Online Features and Print
Markers for the Validation of Reported Dietary Intake in Adults with Cystic Fibrosis
2009, Journal of the American Dietetic Association
Citation Excerpt :
After extraction with hexane, the fatty acid methyl esters were analyzed in a Hewlett-Packard chromatograph (HP4890, Wilmington, DE), equipped with a flame ionization detector and using a BPX75 fused-silica capillary column (SGE, Villebon, France) (21). A 72-hour stool sample was collected (from the fifth day of the questionnaire) for the quantitative measurement of fecal fat and nitrogen by means of a spectrophotometer technique (near infrared reflectance analysis) (32). On the last day of the questionnaire, the patients provided a 24-hour urine sample in 2-L polypropylene bottles that contained 5 g boric acid for conservation (as preservative).
To identify different markers in order to validate the assessment of dietary intake in adults with cystic fibrosis (CF).
Cross-sectional survey.
Tertiary care.
We assessed 37 adults with CF whose nutritional and respiratory condition was stable and 37 healthy adults, matched for age, sex, and nutritional status.
A consecutive, 7-day, prospective dietary survey was given to all the participants. Anthropometric variables were measured and a fasting blood sample was drawn to measure the composition of the serum phospholipid fatty acids by gas chromatography. We also measured fecal fat and nitrogen at 72 hours and 24-hour urine nitrogen.
The ratio of energy intake to basal metabolic rate expenditure was significantly greater in the patients (2.1±0.4) than the controls (1.79±0.4) and the percentage of patients with the ratio of energy intake to basal metabolic rate lower than 1.55 was 24% in the controls (n=9) vs 8% in the patients (n=3). Fecal nitrogen correlated significantly with total energy and the intake of carbohydrates, lipids, and proteins. In the patients, total dietary energy and fat and protein intake correlated positively with fecal fat. The protein and fat intake and fecal nitrogen and fat correlated significantly with urine nitrogen. In the controls, significant correlations were seen between different parameters of intake and the percentage of certain serum phospholipid fatty acids. These correlations in the patients were either absent or less marked.
Use in persons with CF of the energy intake to basal metabolic rate ratio, measurement of fecal fat and nitrogen at 72 hours and of urine nitrogen may be useful to validate dietary surveys. The serum phospholipid fatty acid profile, however, may be less useful for this purpose in these patients.

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Research communicationQuantitative determination of faecal fat, nitrogen and water by means of a spectrophotometric technique: near infrared reflectance analysis (NIRA). Assessment of its accuracy and reproducibility compared with chemical methods

Abstract

J Biol Chem

Clin Chim Acta

Gastroenterology

Gastroenterology

Clin Chim Acta

Clinical chemistry: principles and technics

Research communication
Quantitative determination of faecal fat, nitrogen and water by means of a spectrophotometric technique: near infrared reflectance analysis (NIRA). Assessment of its accuracy and reproducibility compared with chemical methods