Analysis of variance (ANOVA) is one of the most frequently used statistical methods in medical research. The need for ANOVA arises from the error of alpha level inflation, which increases Type 1 error probability (false positive) and is caused by multiple comparisons. ANOVA uses the statistic F, which is the ratio of between and within group variances. The main interest of analysis is focused on the differences of group means; however, ANOVA focuses on the difference of variances. The illustrated figures would serve as a suitable guide to understand how ANOVA determines the mean difference problems by using between and within group variance differences.
Analysis of Variance* ; False Positive Reactions ; Inflation, Economic

PURPOSE: False-positive (FP) results of fecal immunochemical tests (FITs) conducted in colorectal cancer (CRC) screening could lead to performing unnecessary colonoscopies. Hemorrhoids are a possible cause of FP FIT results; however, studies on this topic are extremely rare. We investigated whether hemorrhoids are associated with FP FIT results. MATERIALS AND METHODS: A retrospective study was conducted at a university hospital in Korea from June 2013 to May 2015. Of the 34547 individuals who underwent FITs, 3946 aged ≥50 years who underwent colonoscopies were analyzed. Logistic regression analysis was performed to determine factors associated with FP FIT results. RESULTS: Among 3946 participants, 704 (17.8%) showed positive FIT results and 1303 (33.0%) had hemorrhoids. Of the 704 participants with positive FIT results, 165 had advanced colorectal neoplasia (ACRN) and 539 had no ACRN (FP results). Of the 1303 participants with hemorrhoids, 291 showed FP results, of whom 81 showed FP results because of hemorrhoids only. Participants with hemorrhoids had a higher rate of FP results than those without hemorrhoids (291/1176, 24.7% vs. 248/2361, 10.5%; p<0.001). Additionally, the participants with hemorrhoids as the only abnormality had a higher rate of FP results than those experiencing no such abnormalities (81/531, 15.3% vs. 38/1173, 3.2%; p<0.001). In multivariate analysis, the presence of hemorrhoids was identified as an independent predictor of FP results (adjusted odds ratio, 2.76; 95% confidence interval, 2.24–3.40; p<0.001). CONCLUSION: Hemorrhoids are significantly associated with FP FIT results. Their presence seemed to be a non-negligible contributor of FP results in FIT-based CRC screening programs.
Aged ; Colonoscopy ; Colorectal Neoplasms/*diagnosis ; Confidence Intervals ; Early Detection of Cancer/methods ; False Positive Reactions ; Female ; *Hemorrhoids ; Humans ; Male ; Middle Aged ; Multivariate Analysis ; *Occult Blood ; Odds Ratio ; Regression Analysis ; Republic of Korea ; Retrospective Studies ; Unnecessary Procedures

BACKGROUND: Specific IgE antibodies against the low-molecular-weight carbohydrate antigen that does not bridge IgE molecules on mast cells are not associated with clinical symptoms. Cross reactivity can be determined in allergen-specific IgE detection assays when the carbohydrate structures between pollen allergens and plant derived food allergens are similar; in such cases, false positive results for grain or legume allergens can be reported for pollen allergic patients who are not sensitized to those allergens. This phenomenon arises owing to the presence of cross-reactive carbohydrate determinants (CCDs). OBJECTIVE: This study aimed to assess the impact of CCD interference on the results for pollen allergen-specific IgE antibodies in the general adult population and to perform CCD inhibition tests evaluating the involvement of CCD on samples positive to pollen allergens. METHODS: Serum samples from 322 subjects were tested for IgE antibodies to pollens and CCD. The research subjects were given questionnaires about pollen allergic symptoms to help assess the presence of allergies. Allergen IgE antibodies for Japanese cedar, Japanese cypress, orchard grass, ragweed, MUXF, bromelain, horseradish peroxidase (HRP), and ascorbate oxidase (ASOD) were analyzed. RESULTS: It was observed that among individuals who tested positive to any of the pollen allergens, the positive ratio of CCD-specific IgE antibody was the highest for HRP (13.5%–50.0%). The results from the inhibition tests revealed that CCD was marginally present. Although IgE antibodies for cedar pollen did not react with CCD, IgE antibodies for Japanese cypress, orchard grass, and ragweed might be detected by the presence of CCD. CONCLUSION: The results of the inhibition tests revealed the obvious presence of CCD suggesting its involvement. Considering these findings, careful evaluation of patient IgE results should be performed for Japanese cypress, orchard grass, and ragweed.
Adult ; Allergens ; Ambrosia ; Antibodies ; Ascorbate Oxidase ; Asian Continental Ancestry Group ; Bromelains ; Cryptomeria ; Cupressus ; Dactylis ; Fabaceae ; False Positive Reactions ; Horseradish Peroxidase ; Humans ; Hypersensitivity ; Immunoglobulin E ; Mast Cells ; Plants ; Pollen ; Research Subjects ; Rhinitis, Allergic ; Rhinitis, Allergic, Seasonal

BACKGROUND/AIMS: To evaluate a new monoclonal antibody for Helicobacter pylori urease in gastric tissue. METHODS: A total of 107 volunteers were enrolled. All subjects underwent a 13C-urea breath test and esophagogastroduodenoscopy. Gastric aspirates were analyzed for pH and ammonia. Six biopsy specimens in the gastric antrum and body were obtained for a rapid urease test and histology. The new monoclonal antibody-based H. pylori urease test (HPU) was performed to rapidly and qualitatively detect urease in two biopsy specimens. RESULTS: H. pylori infection was diagnosed in 73 subjects. The sensitivity and specificity of the HPU was 89% and 74%, respectively. The subjects were divided into two groups: one with true-positive and true-negative HPU results (n = 90) and the other with false-positive and false-negative HPU results (n = 17). Across all subjects, ammonia levels were 900.5 +/- 646.7 and 604.3 +/- 594.3 mumol/L (p > 0.05), and pH was 3.37 +/- 1.64 and 2.82 +/- 1.51 (p > 0.05). Sensitivity was higher in the presence of atrophic gastritis or intestinal metaplasia. CONCLUSIONS: HPU detected H. pylori in approximately 10 min. Gastric aspirate ammonia and pH levels did not affect the test results. Sensitivity was good in the presence of atrophic gastritis or intestinal metaplasia.
Adult ; Antibodies, Monoclonal/*immunology ; Bacterial Proteins/*analysis/immunology ; Biomarkers/analysis ; Biopsy ; False Negative Reactions ; False Positive Reactions ; Female ; Gastritis, Atrophic/*diagnosis/microbiology ; Helicobacter Infections/*diagnosis/microbiology ; Helicobacter pylori/*enzymology/immunology ; Humans ; *Immunologic Tests ; Male ; Metaplasia ; Middle Aged ; Predictive Value of Tests ; Pyloric Antrum/*microbiology/pathology ; Reproducibility of Results ; Time Factors ; Urease/*analysis/immunology ; Workflow

BACKGROUNDThe false positive in conventional syphilis serological test was found in patients with multiple myeloma (MM).

OBJECTIVETo investigate the relationship between the M-protein of patients with MM and the false positive in conventional syphilis serologic test.

METHODSThe M-protein of 68 MM cases was typed with immunofixation electrophoresis and 68 cases of MM were screened with non-specific and specific syphilis serologic tests, then the samples with syphilic serological positive were chosen and confirmed with immonobloting test, finally the relationship between M protein of MM and the false positive of syphilis serological test were analysed.

RESULTSFour out of 68 cases showed the positive in syphilis serological test and further were confimed to be false positive by immunoblotting test, the false positive rate was nearly 6%. The M-protein of MM patients in our hospital mostly possessed IgG, κ type, followed by IgA, κ type, light chain κ type. In general, κ : λ = 2.4 : 1. Among samples of 4 cases with syphilis serological positive 2 cases were of IgG and κ type, 1 case was of IgG, λ type, another 1 case was IgA, κ type.

CONCLUSIONThe M-protein of IgG and IgA types in MM patients results in syphilis serological false positive reaction. The clinicians and laboratorial technicians should pay a great attention to screen the MM patients for the false positive syphilis serological test so as to avoid the misdiagnosis and subsequent embarassment.

Diagnostic Errors ; False Positive Reactions ; Humans ; Immunoglobulin A ; classification ; Immunoglobulin G ; classification ; Multiple Myeloma ; diagnosis ; Myeloma Proteins ; metabolism ; Syphilis ; diagnosis ; Syphilis Serodiagnosis

Adolescent ; Adult ; Aged ; Aged, 80 and over ; Eating ; Esophagoscopy ; Esophagus ; diagnostic imaging ; surgery ; False Positive Reactions ; Foreign Bodies ; diagnosis ; diagnostic imaging ; Foreign-Body Migration ; diagnosis ; diagnostic imaging ; Humans ; Middle Aged ; Pharynx ; diagnostic imaging ; surgery ; Radiography ; Remission, Spontaneous ; Retrospective Studies ; Tomography, X-Ray Computed ; Young Adult

OBJECTIVETo explore the effect of false positive signals during detection of BCR/ABL fusion gene by fluorescence in situ hybridization (FISH), and develop a method for calibration.

METHODSNormal specimens were mixed with BCR/ABL positive specimens in which presented signal pattern of 1-red-2-green-1-fusion (1R2G1F) using dual color dual fusion (DCDF) probes and 1-red-1-green-1-fusion (1R1G1F) using extra signal (ES) probes in different proportions. Mixed samples were detected using DCDF and ES probes. Results of DCDF probes, ES probe before calibration, ES probes after calibration and theoretical results were compared by binomial distribution in different proportions.

RESULTSThe rate of false positive signals has risen with increase of negative rate. A significant difference was found between theoretical proportion and results without calibration in negative level, 5%, 10% and 25% positive level (P<0.05). There was no significant difference between theoretical proportion and results without calibration in 50% and 90% positive level (P>0.05). Also there was no significant difference between theoretical proportion and calibrated results (P>0.05).

CONCLUSIONCalibration of FISH result can delimitate the effect of false positives, and can provide more reliable results in cases with low level positive rates.

Adult ; Calibration ; False Positive Reactions ; Female ; Fusion Proteins, bcr-abl ; genetics ; Humans ; In Situ Hybridization, Fluorescence ; methods ; standards ; Leukemia, Myelogenous, Chronic, BCR-ABL Positive ; diagnosis ; genetics ; Young Adult

The incidence rate of cervical cancer in Korea is still higher than in other developed countries, notwithstanding the national mass-screening program. Furthermore, a new method has been introduced in cervical cancer screening. Therefore, the committee for cervical cancer screening in Korea updated the recommendation statement established in 2002. The new version of the guideline was developed by the committee using evidence-based methods. The committee reviewed the evidence for the benefits and harms of the Papanicolaou test, liquid-based cytology, and human papillomavirus (HPV) testing, and reached conclusions after deliberation. The committee recommends screening for cervical cancer with cytology (Papanicolaou test or liquid-based cytology) every three years in women older than 20 years of age (recommendation A). The cervical cytology combined with HPV test is optionally recommended after taking into consideration individual risk or preference (recommendation C). The current evidence for primary HPV screening is insufficient to assess the benefits and harms of cervical cancer screening (recommendation I). Cervical cancer screening can be terminated at the age of 74 years if more than three consecutive negative cytology reports have been confirmed within 10 years (recommendation D).
Adult ; Age Factors ; Aged ; Early Detection of Cancer/adverse effects/*methods/standards ; Evidence-Based Medicine ; False Positive Reactions ; Female ; Humans ; Hysterectomy ; Middle Aged ; Papillomavirus Infections/diagnosis ; Papillomavirus Vaccines ; Patient Selection ; Pregnancy ; Pregnancy Complications, Neoplastic/diagnosis ; Republic of Korea ; Review Literature as Topic ; Uterine Cervical Neoplasms/*diagnosis ; Vaginal Smears/adverse effects/methods/standards ; Young Adult

Heterophilic antibodies are human immunoglobulins directed against various animal antigens. They can produce false-positive results in the analysis of different tumor markers, including prostate-specific antigen. This interference can lead to misdiagnosis, unnecessary tests, and overtreatment in some cases. We present herein the case of a 52-year-old man with repeated spurious elevation of prostate-specific antigen, reaching levels of 108.7 ng/mL, that were suspected to be caused by heterophilic antibodies. The interference was solved by changing the analysis technique. Real values of prostate-specific antigen were less than 1 ng/mL.
Antibodies, Heterophile/*immunology ; False Positive Reactions ; Humans ; Luminescence ; Male ; Middle Aged ; Prostate-Specific Antigen/*blood ; Prostatic Neoplasms/blood/*diagnosis/immunology

No abstract available.
Bronchi/microbiology/pathology ; Coronavirus Infections/*microbiology/*pathology ; Delayed Diagnosis/*prevention & control ; Diagnosis, Differential ; Diagnostic Errors/*prevention & control ; False Positive Reactions ; Humans ; Male ; Middle Aged ; Reproducibility of Results ; Sensitivity and Specificity ; Specimen Handling/methods ; Sputum/*cytology/*microbiology