Consensus on the use and interpretation of cystic fibrosis mutation analysis in clinical practice.

It is often challenging for the clinician interested in cystic fibrosis (CF) to interpret molecular genetic results, and to integrate them in the diagnostic process. The limitations of genotyping technology, the choice of mutations to be tested, and the clinical context in which the test is administered can all influence how genetic information is interpreted. This paper describes the conclusions of a consensus conference to address the use and interpretation of CF mutation analysis in clinical settings. Although the diagnosis of CF is usually straightforward, care needs to be exercised in the use and interpretation of genetic tests: genotype information is not the final arbiter of a clinical diagnosis of CF or CF transmembrane conductance regulator (CFTR) protein related disorders. The diagnosis of these conditions is primarily based on the clinical presentation, and is supported by evaluation of CFTR function (sweat testing, nasal potential difference) and genetic analysis. None of these features are sufficient on their own to make a diagnosis of CF or CFTR-related disorders. Broad genotype/phenotype associations are useful in epidemiological studies, but CFTR genotype does not accurately predict individual outcome. The use of CFTR genotype for prediction of prognosis in people with CF at the time of their diagnosis is not recommended. The importance of communication between clinicians and medical genetic laboratories is emphasized. The results of testing and their implications should be reported in a manner understandable to the clinicians caring for CF patients.

Analysis of the positivity rate in IgE positive patients to inhalant allergens in Verona Hospital Laboratory during 2002-2003.

BACKGROUND: At present test tube allergy diagnosis is becoming increasingly more comparable to skin prick tests and is therefore increasingly more reliable, not only from an analytical point of view but also from a clinical one. The cost of test tube allergens has decreased over the years and the specific IgE dosage can quickly give a good diagnostic indication. OBJECTIVE: To study the percentage of positive subjects for each individual allergen in cases of suspected allergy, the laboratory can easily identify, also by age bracket, the positivity for those well known allergens that are more commonly responsible for allergic pathologies by using the skin prick test. Our laboratory has studied the test tube diagnostic activity of 2002 and 2003. The inhaled allergens used to identify the positivity percentage were selected from those in our Allergy Unit and which literature identifies as those more commonly positive at skin prick tests. METHODS: The positivity rate of specific IgEs (UniCAP100- Phamarcia) were analyses for two age brackets before and after the age of 12. The younger than 12 group was then subdivided further into pre-school age (3-5 years) and school age (6-12). RESULTS: It can be stated that in the grass group, the seasonal allergens, the most commonly positive were cereals and pellitory, the latter increasing in adult age (above 12 years). In the tree group of seasonal allergens, positivity was found to increase in adult age for olive and cypress trees. The more commonly positive perennial allergens in the adult age (above 12) are dermathophagoides and cat. Below 12, there is a strong positivity to alternaria. CONCLUSIONS: Such test tube studies on IgE positivity are not only useful for better defining diagnostic patterns to give an initial idea of suspected allergy, but also to highlight any changes in the IgE antibody count within different age brackets, with the possibility of documenting the progress of the pathology which is characteristic of the allergy in question.

Analysis of the positivity rate in IgE positive patients to food allergens in Verona Hospital laboratory during 2003.

BACKGROUND: It has been known for some time now that reactions to allergens, not only those inhaled but also those in food, varies with age in atopical patients. OBJECTIVE: To evaluate the specific IgE positivity percentage in order to improve laboratory diagnosis in subjects with suspected food allergy. METHODS: The positivity percentages of specific IgE were analysed (UniCAP100-Pharmacia) taking into consideration the two age brackets of below and above 12 years. The below 12 years age bracket was then further divided into pre-school age (3-5 years) and school age (6-12 years). RESULTS: By measuring the simple positivity percentage for specific IgE to food allergens, there is a clear decrease as the child matures in reactions to milk and eggs and an increase towards food IgEs that cross-react with grass and tree pollens or other inhaled allergens like moulds and mites. CONCLUSION: It will be necessary in the future to have the diagnostic means to identify this cross-reaction problem by using recombinant allergens that can demonstrate the combined reaction between inhaled and food allergens.

Variability between methods to determine ANA, anti-dsDNA and anti-ENA autoantibodies: a collaborative study with the biomedical industry.

This study was performed by the Italian Society of Laboratory Medicine (SIMeL) in order to establish the variability between the different analytical systems currently used in clinical laboratories for the detection of autoantibodies diagnostic of systemic autoimmune disease. Sixteen industrial, and two university laboratories participated in this study which entailed the determination of anti-nuclear (ANA), anti-dsDNA and anti-ENA antibodies in 11 sera from patients with clinically diagnosed systemic rheumatic disease, using reagents produced by these companies and different methodologies (indirect immunofluorescence, immunoenzymatic assay, counterimmunolectrophoresis, immuno and western blotting). We found 93.5% agreement between the methods used for the detection of ANA, 85.2% for anti-dsDNA antibodies, and 86.9% for anti-ENA antibodies. Among the anti-ENA antibodies, regardless of the method used, detection percentages were excellent for anti-RNP and anti-SSB/La (100%), good for anti-SSA/Ro (93%), but unacceptable for the anti-Jo-1 (67%), anti-Scl70 and anti-Sm (47%) antibodies. This further stresses the need for rigorous standardisation of commercial reagents and analytical procedures, as well as the introduction of external quality assessment (EQA) programs, and a complete definition of operative protocols adjusted to the sensitivity and specificity of the various methods.

Sysmex SE-9000 hematology analyzer: performance evaluation on leukocyte differential counts using an NCCLS H20-A protocol. National Committee for Clinical Laboratory Standards.

We evaluated the performance (ie, imprecision, inaccuracy, and analytic sensitivity) of the Sysmex SE-9000 commercial hematology analyzer (TOA Medical Electronics, Kobe, Japan) on differential leukocyte counts according to the National Committee for Clinical Laboratory Standards H20-A protocol. The results obtained were compared with those from the Bayer H6000 and H3 (Bayer Diagnostic Division, Tarrytown, NY), the Coulter MAXM (Miami, Fla), and the microscopic method. Altogether, samples from 462 subjects were analyzed. The results show a substantial superimposition of reference intervals between the methods. The imprecision of the SE-9000 is low for all the leukocyte subpopulations, with the exception of basophils (coefficient of variation: neutrophils, 3.35%; lymphocytes, 4.25%; monocytes, 7.9%; eosinophils, 9.5%; and basophils, 44.2%) and is consistently lower than that of manual counts. The correlation with other methods is high, with the exception of basophils (r2: neutrophils, 0.94-0.95; lymphocytes, 0.93-0.97; monocytes, 0.76-0.85; eosinophils, 0.96-0.99; and basophils, 0.02-0.56). When compared with the microscopic method, an overestimation of neutrophils is seen mostly at low concentrations (mean difference, 2.63), and an underestimation of lymphocytes is seen at high concentrations (mean difference, -3.1). The clinical sensitivity was good, with an agreement of 75.7% on morphologic and 89.6% on distributional abnormalities. With a new analytical channel for immature cells (IMI), the analyzer shows high sensitivity in detecting immature cells of the granulocytic lineage (from 94.4% for immature granulocytes to 96% for myeloblasts).

Evaluation of four automated hematology analyzers. A comparative study of differential counts (imprecision and inaccuracy).

The authors evaluated the performance of four modern, commercially available hematology analyzers for imprecision and inaccuracy in determining the leukocyte differential count. The evaluation was performed according to International Committee for Standardization in Haematology protocols and the National Committee for Clinical Laboratory Standards H20-T standard, using the same group of patients simultaneously. Imprecision was very low among all the analyzers for neutrophils and lymphocytes (coefficient of variation maximum = 4.12%), whereas for the other leukocyte populations it tended to increase as their presence percentage decreased. The imprecision of the analyzers was still lower than that of the microscopic method. The correlation with the manual 800 cell count (inaccuracy) was good for neutrophils, lymphocytes, and eosinophils (r = 0.974 to 0.888), less so for monocytes (r = 0.757 to 0.490), whereas it was poor for basophils (r = 0.532 to 0.078).

Flow cytometric reticulocyte counting. Parallel evaluation of five fully automated analyzers: an NCCLS-ICSH approach.

We performed a parallel evaluation of 5 automated reticulocyte analyzers. The guidelines were those proposed by the National Committee for Clinical Laboratory Standards and the International Council for Standardisation in Haematology. Duplicate analyses were performed for 225 healthy subjects and 115 patients affected by various diseases. The reference intervals were different for each method (ADVIA 120, 27-125 x 10(3)/microL [27-125 x 10(9)/L]; CELL DYN 4000, 25-108 x 10(3)/microL [25-108 x 10(9)/L]; GEN-S, 20-85 x 10(3)/microL [20-85 x 10(9)/L]; SE 9500 RET, 23-95 x 10(3)/microL [23-95 x 10(9)/L]; and VEGA RETIC, 30-130 x 10(3)/microL [30-130 x 10(9)/L]). The comparisons of percentage counts with the microscopic reference method were satisfactory for all automated methods. However, a tendency to overestimate at low counts was noted. This progressively increased from the SE 9500 RET to the VEGA RETIC. The imprecision was excellent for all the methods at normal and high concentrations. This was higher at low concentrations. When compared with the microscopic reference, the analyzers showed satisfactory sensitivity at low counts and excellent sensitivity at high counts. The overall agreement varied from 74.8% for the GEN-S to 86.1% for the SE 9500 RET.

A clinical evaluation of monoclonal (CA19-9, CA50, CA12-5) and polyclonal (CEA, TPA) antibody-defined antigens for the diagnosis of pancreatic cancer.

We measured in 193 patients, admitted to our wards for symptoms and signs suggestive of pancreatic or digestive malignancy, the serum levels of five tumor-associated antigens (CA 19-9, CA 50, CA 125, TPA, CEA) and we evaluated their diagnostic accuracy both when used alone and in combination. For CA 19-9 and CA 50 a sensitivity for pancreatic cancer as high as 92 and 88%, respectively, and specificity of 91.8% were found. A lower sensitivity vs. pancreatic cancer was found for the other tumor markers, and vs. the other digestive and nondigestive malignancies for all tumor markers (apart for CA 19-9 and CA 50 vs. biliary carcinomas). As for the combined assays, the best figures were found vs. pancreatic cancer for CA 19-9 plus CA 50, CA 50 plus CEA, CA 50 plus CA 125; a sensitivity by far worse vs. the other gastrointestinal cancers was found for all the possible combinations. We conclude that in selected symptomatic patients some tumor-marker determinations can be useful in identifying those with a high probability of harboring a pancreatic cancer, to be further studied or operated upon. The clinical relevance of this in patients already symptomatic is at present unclear.

Isoelectric focusing on cellulose acetate membrane: a separation procedure for alkaline phosphatase isoenzymes.

An isoelectric focusing technique for the separation of alkaline phosphatase isoenzymes on cellulose acetate membrane is described. Optimal conditions for isoelectric focusing were established by changing ampholine concentration and focusing conditions. Bone, liver, intestinal, and placental isoenzymes can be resolved into various sub-bands in a pH range of 4.1 to 5.2. These sub-bands were correlated with the findings of electrophoretic isoenzyme separation. The whole procedure proves very simple to perform and comparatively time saving (4 h). This procedure may help clarify the problems of ALP isoenzyme differentiation when electrophoretic patterns are unresolved.

Enzyme immunoassay for pancreatic lipase: comparison with turbidimetric method in pancreatic diseases.

We report the results of the analytical and clinical evaluation of a specific enzyme immunoassay for determination of human pancreatic lipase, in comparison with a turbidimetric method, in pancreatic pathology. Under standardized conditions of incubation time and temperature we found intraassay coefficient of variation (CV) of 1.3, 3.2, 2.1% at means = 18.7, 43.7, 224 micrograms/L and interassay CV of 2.8, 4.6, 3.0% at means = 19, 42.6, 230 micrograms/L, respectively. In general, a good correlation (r = 0.97) was found between lipase determined as a protein or through its catalytic activity. No significant correlation (r = 0.38) was observed with samples containing low concentration of lipase (up to 18 micrograms/L). We conclude that the turbidimetric method is reliable for routine determinations in the diagnosis of acute pancreatic pathology. However, the better sensitivity of the immunochemical assay should provide additional information for monitoring pancreatic insufficiency.

Macro creatine kinase type 2: a marker of myocardial damage in infants?

The case histories of two children (aged two months) affected by myocarditis showing an atypical band of serum creatine kinase (EC 2.7.3.2; CK) in the CK isoenzyme electrophoretic pattern are reported. The electrophoretic mobility on cellulose acetate of the atypical iso-CK band and its greater relative molecular mass, the lack of binding with immunoglobulins and the result of CK-BB determination by RIA, allowed us to identify the band with an oligomeric form of the mitochondrial isoenzyme. One child died 2 days after admission, while in the other it was possible to demonstrate reduction and disappearance of the atypical band in concomitance with a marked clinical improvement. Our findings suggest that the oligomeric form of mitochondrial-CK is released in conditions of serious heart muscle damage, and that it may be an indicator of myocardial cellular necrosis in pediatric patients.

Comparison of different pharmacological interventions on enzymatic parameters during acute myocardial infarction.

The concept that acute myocardial infarction is a dynamic event and that different interventions can modify the extent of the necrosis, has led to renewed interest in early pharmacological and surgical treatments designed to reduce the ischemic injury. To evaluate the effects of different pharmacological interventions aimed to reduce the extent of necrosis, we studied 166 patients (138 male and 28 female, mean age of 59.4 +/- 11.3 years) admitted within 6 h after chest pain and treated with a single therapy during the first 72 h. Enzymatic infarct size (IS) was calculated by serial creatine kinase isoenzyme MB determinations using a compartmental model. Six groups of patients were evaluated: 33 patients were treated only with antiplatelet drugs, 38 with anticoagulants, 34 with intravenous thrombolytic therapy, 20 with calcium channel blockers, 25 with nitrates, and 16 with beta-blockers. Estimated IS (gEq/m2) and elimination constant (Kd, U/L/h) did not differ in the six groups, but patients treated with streptokinase had higher release constant (Ka, U/L/h) and shorter time to peak CK-MB value. Early treatment (less than or equal to 2 h after chest pain) had a favourable effect on the enzymatic IS only in patients treated with calcium channel blockers (p less than 0.005).

CPK and CPK-MB in the early diagnosis of acute myocardial infarction and prediction of infarcted area.

This study was carried out on patients of a coronary unit to evaluate the diagnostic efficiency of total CPK and CPK-MB by using different analytical techniques: catalytic, immunoassisted, cellulose acetate electrophoresis, radioimmunoassay and immunoradiometric assay. The behaviour of the enzyme was studied in all patients with reference to the localization and extent of the infarct. In all cases a diagnostic algorithm was followed based on the combined use of CPK and its MB isoenzyme; the activity was measured twice, at three-hour intervals after admission. In this way the utilization of total CPK and MB isoenzyme allows almost complete diagnostic efficiency within the first 9 hours from onset of chest pain, together with the possibility of calculating the slope of the curve of MB isoenzyme release useful for calculating infarct size. Maximum diagnostic efficiency is also obtained in cases of small infarcts, with silent ECG, and those difficult to classify clinically.

Isolated rectal relapse in non Hodgkin lymphoma patient.

The authors report on case of isolated rectal relapse of non Hodgkin lymphoma after complete remission with chemotherapy. They analyse diagnostic and therapeutic aspects, on the grounds of literature data and personal experience.

Evaluation of diagnostic reliability of DCA 2000 for rapid and simple monitoring of HbA1c.

The monitoring of diabetic patients by evaluating glycated protein levels is now widely accepted and performed. The microchromatographic version of the high performance liquid chromatography method is the technique most frequently used in clinical practice. The DCA 2000 instrument (Bayer Diagnostics, Milan, Italy), based on an immunochemical technique, has been proposed for the rapid and simple evaluation of HbAlc, using even capillary blood. We evaluated 171 subjects including 22 healthy volunteers, 78 type 2 diabetic patients with different degrees of metabolic control, 11 women affected by gestational diabetes mellitus (GDM), 6 patients with hyperlipemia, 38 patients with chronic renal failure, 13 diabetic patients with chronic renal failure, and 3 patients with hemoglobinopathies. The DCA 2000 model was compared with the Diamat HPLC system. Data from within-run imprecision studies showed excellent precision, for both DCA 2000 and the HPLC system. The correlation between the two different systems, as shown by other statistical evaluations, was good (y = 0.911x + 0.462, r = 0.923). Results from the control group and diabetic patients were used to compare the two methods. Values obtained using the DCA 2000 were significantly lower (p < 0.0001) than those obtained with the HPLC system, in both healthy subjects and diabetic patients. To detect possible interferences, selected samples were analyzed from patients with hyperlipemia, diabetes and chronic renal failure, and hemoglobinopathies. While in the case of hyperlipemia, an acceptable correlation coefficient between the two systems was confirmed (y = 1.047x - 1.236, r = 0.876), in the case of chronic renal failure the correlation turned out to be very low (y = 0.254x + 3.456, r = 0.203). Our results indicate that the DCA 2000 gives accurate and reliable results in the clinical field of interest.

Laboratory evaluation of the Miles H.3 automated reticulocyte counter. A comparative study with manual reference method and Sysmex R-1000.

OBJECTIVE: To evaluate the performance of the new commercial Miles H.3 RTX analyzer in counting reticulocytes. METHODS AND PATIENTS: The results from the counter were compared to those obtained from microscopic methods, following the National Committee for Clinical Laboratory Standards H44-P guidelines, and to the results from the Sysmex R-1000 counter. In total, 279 samples were analyzed in duplicate with each of the three methods. One hundred thirty-three samples were from healthy subjects, while 146 were from patients with various pathologies, 10 of whom presented with posttherapeutic aplasia of the bone marrow and 9 with iron-deficiency anemia. RESULTS: The reference intervals for the normal controls are different for each of the three methods (manual: 0.35-2.35%, 16 to 116 x 10(9)/L; Miles H.3: 0.65-2.30%, 35.1 to 112.0 x 10(9)/L; Sysmex R-1000: 0.6-1.85%, 28.0 to 85.0 x 10(9)/L). The overall imprecision was lower for the instruments than for the microscopic method (Miles H.3: coefficient of variation, 11.6%; R-1000: coefficient of variation, 4.2%; microscopic method: coefficient of variation, 24.2%). The Miles H.3 shows a good correlation with the other methods, yet it overestimated the low values with respect to both the microscopic method (intercept, 0.55; slope, 0.70) and the R-1000 (intercept, 0.44; slope, 0.78). This became particularly pronounced in patients with marrow aplasia. CONCLUSIONS: Miles H.3 can produce results with an acceptable degree of accuracy. The agreement with the dedicated fluorescence-based flow cytometer R-1000 at normal and high concentrations is also good. The possibility of providing reticulocyte indices as well as erythrocyte indices (mean volume, mean hemoglobin content, mean hemoglobin concentration) and the relative dispersion indices could be useful in understanding red cell pathophysiology in normal and iron deficient patients.

Modification of serum proteins in guinea pigs immunized and challenged with toluene diisocyanate.

OBJECTIVES: Guinea pigs were used to determine whether immunization and challenge by toluene diisocyanate (TDI) induce changes in the serum protein concentrations of the "acute-phase response" and whether TDI can form adducts with serum proteins. METHODS: Guinea pigs were immunized by weekly intradermal injections of TDI and challenged with TDI 7 days after the 3rd injection. The animals were killed 6 hours after the challenge, and serum was analyzed for protein characterization by gel electrophoresis and for specific antibodies to TDI by enzyme-linked immunosorbent assay (ELISA) and Western blotting. RESULTS: The total serum protein concentration of the immunized TDI-challenged guinea pigs increased in comparison with that of nonimmunized animals [75 (SE 0.7) versus 47.4 (SE 2.3) mg/ml; ]. Albumin and alpha, and alpha2 globulins increased significantly [respectively: 65.8 (SE 0.2)%, 2.1 (SE 0.1)% and 7.2 (SE 0.1)% versus 59 (SE 1.3)%, 1.3 (SE 0.1)% and 3.7 (SE 0.1)%], whereas beta1 and beta2 globulins decreased in the immunized TDI-challenged guinea pigs [7.8 (SE 0.2)% and 0.8 (SE 0.2)% versus 15.8 (SE 0.7)% and 4.8 (SE 0.2)%]. The gamma globulin concentrations did not change significantly. In the immunized TDI-challenged animals, albumin was modified by TDI and ran faster on agarose gel electrophoresis than did albumin from nonimmunized guinea pigs. In the ELISA, only immunized animals had high titers of TDI-specific antibodies (IgG and IgG1); by blotting, the antibodies reacted against TDI, the TDI-BSA-conjugate and several TDI-conjugated guinea pig serum proteins, but they did not react against any native or denaturated serum protein when unconjugated with TDI. CONCLUSIONS: These findings indicate that, in guinea pigs, immunization and challenge with TDI induces changes in serum proteins of the "acute phase response" and TDI is adducted to serum proteins with different molecular weights (eg, albumin).

Serum pancreatic enzyme alterations in acute viral hepatitis.

In a group of 167 patients with acute viral hepatitis (AVH), 11 with type A hepatitis, 125 with type B and 31 type non A, non B, the following enzymes were studied: serum amylase (S-AMY) and its isoenzymes (pancreatic and salivary type), urinary amylase (U-AMY), serum lipase (S-TGL) and serum immunoreactive trypsin (i-TRY). In all groups of patients, in the acute phase of illness, a significant increase in S-AMY was observed, in particular in hepatitis type B and non A, non B (p less than 0.001). An increase in U-AMY excretion was recorded in patients with type A hepatitis. S-TGL levels were significantly higher in all groups, especially in patients with type A hepatitis. i-TRY was only slightly higher in patients with hepatitis A and non A, non B. S-AMY isoenzymes showed a peculiar pattern: the pancreatic type (2) of isoamylase was found to be prevalent in 66% of patients with AVH while in controls the salivary type (1) was prevalent in most cases. Pancreatic enzyme alterations correlated neither with laboratory hepatic function tests nor with the clinical syndrome. These results suggest that a pancreatic injury is not uncommon in AVH, although it is seldom severe.

Biochemical and cytochemical effects of cytosine arabinoside (ARA C) and hydrocortisone on HeLa cells.

The biochemical and cytochemical effects of cytosine arabinoside (Ara C) and of hydrocortisone on HeLa cell in vitro have been studied. In cultures treated with Ara C, a relationship exists between the cytocidal effects of the drug and an increase in alkaline phosphatase. Although hydrocortisone had no influence on the proliferative rhythm, it induced an increase in alkaline phosphatase. Results obtained with the cytochemical technique were evaluated, particularly in relation to enzyme localization.

[Macroamylasemia or pancreatitis? A diagnostic problem]. / Macroamilasemia o pancreatite? Un problema diagnostico.

Macroamylasemia is a condition characterized by a serum amylase activity increase due to complex macromolecules whose large size prevents its urinary excretion. It cannot be consistently correlated with any particular disease state, and should be regarded as a benign chemical derangement. The major clinical importance of macroamylasemia is the confusion of this condition with other causes of hyperamylasemia and its prevalence in the population, comprised between 1 and 2%. Macroamylasemia should be considered in any patient with elevated levels of serum amylase activity whose serum lipase and urine amylase levels are normal, in the face of unimpaired renal function. Confirmation rests on the demonstration of a macromolecular amylase component in the serum by means of chromatography, ultracentrifugation and electrophoresis. In this report, we, describe a patient with chronic liver disease caused by alcohol, occasional abdominal pain and persistent hyperamylasemia, though to be due to pancreatitis, but subsequently shown to be due to a macroamylase.