OSOMÃ‚Â® Ultra Strep A Test - Sekisui Diagnostics

126 dropsUltra Strep A Test34 5610x2 min 5 minPOSITIVENEGATIVEINVALIDRev. 3098-1, 12/12®

®Ultra Strep A TestCLIA Complexity: WaivedINTENDED USEThe OSOM ® Ultra Strep A Test is a color immunochromatographic assay intended for the qualitativedetection of Group A Streptococcal antigen directly from throat swab specimens.SUMMARY AND EXPLANATION OF TESTGroup A Streptococcus is one of the most important causes of acute upper respiratory tract infection.Early diagnosis and treatment of Group A Streptococcal pharyngitis has been shown to reduce theseverity of symptoms and further complications such as rheumatic fever and glomerulonephritis (1) .Conventional identification procedures for Group A Streptococcus from throat swabs involve theisolation and subsequent identification of viable pathogens by techniques that require 18 to 24 hoursor longer (2) . The OSOM Ultra Strep A Test detects either viable or nonviable organisms directly from athroat swab, providing results within 7 minutes.PRINCIPLES OF TESTThe OSOM Ultra Strep A Test is a color immunochromatographic assay using Dual Label Technology(DLT)**. DLT uses antibody labeled color particles coated at two separate locations in the test device.DLT allows greater sensitivity than the conventional single label technology without sacrificing specificity.In the test procedure, a throat swab is subjected to a chemical extraction of a carbohydrate antigenunique to Group A Streptococcus. The Test Stick is then placed in the extraction mixture and the mixturemigrates along the membrane. If Group A Streptococcus is present in the sample, it will form complexeswith the anti-Group A Streptococcus antibody conjugated color particles located at two separatelocations on the Test Stick. The complex will then be bound by the anti-Group A Streptococcus captureantibody and a visible blue Test Line will appear to indicate a positive result. A red Control Line will alsoappear to indicate the test is valid.KIT CONTENTS AND STORAGEContents:25 Test Sticks Coated with Rabbit Anti-Group A Streptococcus25 Test Tubes25 Sterile Swabs25 Extraction Reagent Bottles (2 M Sodium Nitrite and One Ampule with 0.3 M Acetic Acid)1 Positive Control (Nonviable Group A Streptococci, 0.1% Sodium Azide)1 Negative Control (Nonviable Group C Streptococci, 0.1% Sodium Azide)1 Workstation1 Directional InsertNote: extra components (swabs, tubes) have been provided for your convenience.• Store Test Sticks and reagents tightly capped at 15˚ – 30˚C (59˚– 86˚F).• Do not use Test Sticks or reagents after expiration date.• Store Extraction Reagent Bottles inside the box. Avoid exposure to light.• Avoid dropping Extraction Reagent Bottles as this may cause ampule breakage.MATERIALS REQUIRED BUT NOT PROVIDEDA timer or a watch.PRECAUTIONS• For in vitro diagnostic use.• Follow your laboratory safety guidelines in the collection, handling, storage and disposal of controls,patient specimens and all items exposed to patient specimens (3) .• Caution: The Extraction Reagent Bottle contains Sodium Nitrite and may be harmful if swallowed.Do not taste or swallow. Wash thoroughly after handling.• The Extraction Reagent Bottle contains a glass ampule. Crush the glass ampule with care.• Warning: The Extraction Reagent Bottle contains an acidic solution that will cause skin and eyeirritation. If the solution comes in contact with the skin or eyes, flush with large volumes of water.• If no glass ampule is inside the Extraction Reagent Bottle or the glass ampule appears to be brokenbefore use (reagent is colorless or yellow), discard and use another Extraction Reagent Bottle.• The Positive and Negative Controls contain sodium azide which may react with lead or copperplumbing to form potentially explosive metal azide. Large quantities of water must be used to flushdiscarded control material down a sink.• Do not interchange or mix components from different kit lots.SPECIMEN COLLECTION AND PREPARATION• Collect specimens with a sterile swab from the tonsils and/or the back of the throat (2) taking care toavoid the teeth, gums, tongue or cheek surfaces.• Do not use swabs with cotton tips, wooden shafts or calcium alginate swabs.• Do not use a collection system that contains charcoal or semisolid transport media.

• If your lab requires a culture result as well as the OSOM Ultra Strep A Test result, streak the culture platewith the swab before starting the OSOM Ultra Strep A Test procedure as the extraction reagents willcause the specimen to become nonviable.• Process the swab as soon as possible after collecting the specimen. If you do not perform the OSOMUltra Strep A test immediately, store the swabs either at room temperature or refrigerated for up to 48hours. The swabs and the test kit must be at room temperature prior to running the test.• Sample Transport:• Because the performance characteristics of this product were established with the sterile rayonswabs supplied with the kit, we recommend using these swabs to assure optimal performance.You may purchase the kit swabs in a double swab/dry tube format as an accessory(Sekisui Diagnostics Part #7784).• Because the test does not require live organisms for processing, a rayon transport swabcontaining Stuart’s or Amies media may also be used; however, swabs from other suppliers havenot been validated.QUALITY CONTROLInternal Procedural ControlsThe OSOM Ultra Strep A Test provides three levels of procedural controls with each test run:• The color of the liquid changes from pink to light yellow after the glass ampule is crushed and theextraction reagents are mixed. This is an internal extraction reagent control. The color change meansyou have mixed the extraction reagents properly. The color change also means that the reagents arefunctioning properly.• The red Control Line is an internal positive procedural control. For the Test Stick to be working properly,capillary flow must occur. The Test Stick must absorb the proper amount of sample and the Test Stickmust be working properly for the red Control Line to appear.• A clear background is an internal background negative procedural control. If no interferingsubstances are in the specimen and the Test Stick is working properly, the background willclear. A discernible result will be seen.If the red Control Line does not appear the test is invalid. If the background does not clear and interfereswith the test result, the test is invalid. Call Sekisui Diagnostics Technical Service if you experienceeither of these problems.External Quality Control TestingEach kit contains Positive and Negative Control material. The controls are for external quality controltesting. Use the Controls to test that the extraction reagents and the Test Sticks are working properly.Also use the Controls to test that you are able to correctly perform the test procedure, including theantigen extraction portion of the test procedure. If you choose, you may use Group A and non GroupA Streptococcus ATCC reference strains as external controls. Some commercial controls may containinterfering additives. Therefore Sekisui Diagnostics recommends that you do not use commercialcontrols with the OSOM Ultra Strep A Test.Quality Control requirements should be established in accordance with local, state and federalregulations or accreditation requirements. Minimally, Sekisui Diagnostics recommends that positive andnegative external controls be run with each new lot and with each new untrained operator.QC Testing Procedure:Positive Control• Follow Steps 1 and 2 in the TEST PROCEDUREsection to dispense the Extraction Reagentinto the Test Tube.• Vigorously mix the Positive Control material.Add 1 free falling drop of the Positive Controlfrom the dropper bottle into the Test Tube.• Using a clean swab, follow steps 3 – 6 in theTEST PROCEDURE section to test the swab.Negative Control• Follow Steps 1 and 2 in the TEST PROCEDUREsection to dispense the Extraction Reagentinto the Test Tube.• Vigorously mix the Negative Control material.Add 1 free falling drop of the Negative Controlfrom the dropper bottle into the Test Tube.• Using a clean swab, follow steps 3 – 6 in theTEST PROCEDURE section to test the swab.LIMITATIONSAs with all diagnostic assays, the results obtained by this test yield data that must be used only as anadjunct to other information available to the physician. The following factors must be considered toobtain reliable results:• The OSOM Ultra Strep A Test is a qualitative test for the detection of Group A Streptococcal antigen.This test detects both viable and non-viable Group A Streptococci, and may yield a positive resultin the absence of living organisms.• The quality of the test depends on the quality of the sample; proper throat swab specimens must beobtained. Negative results can occur from inadequate specimen collection or antigen level whichis below the detection limit of the test.• The OSOM Ultra Strep A Test should be used only with throat swab specimens. The use of swabspecimens taken from other sites or the use of other samples such as saliva, sputum or urine hasnot been established.• This test does not differentiate between carriers and acute infection.• Pharyngitis may be caused by viral or bacterial pathogens other than Group A Streptococcus (1,2) .• If the test result is inconsistent with the clinical symptoms, a second throat swab should be collectedfor repeat testing.The American Academy of Pediatrics states (4) : “Several rapid diagnostic tests for GAS pharyngitis areavailable... The specificities of these tests generally are very high, but the reported sensitivities varyconsiderably. As with throat cultures, the accuracy of these tests is most dependent on the quality of thethroat swab specimen, which must contain pharyngeal and tonsillar secretions, and on the experienceof the person who is performing the test. Therefore, when a patient suspected of having GAS pharyngitishas a negative rapid streptococcal test, a throat culture should be obtained to ensure that the patient

does not have GAS infection.” It also states: “Cultures that are negative for GAS infection after 24 hoursshould be incubated for a second day to optimize isolation of GAS.”EXPECTED RESULTSApproximately 19% of all upper respiratory tract infections are caused by Group A Streptococci (5) .Streptococcal pharyngitis displays a seasonal variation and is most prevalent during winter and earlyspring. The highest incidence of this disease is found in crowded populations such as military basesand in school-age children (6) .PERFORMANCE CHARACTERISTICSSummaryThe study results in this section show that the sensitivities of the OSOM Ultra Strep A Test and the standardsingle swab culture method are not statistically different. The study also compared the OSOM Ultra StrepA Test to Rigorous Gold Standard and another commercially available rapid test, Inverness Medical –BioStar’s Strep A OIA ® Max Test***.Comparison of the Performances of OSOM Ultra Strep A Test, Strep A OIA Max Test and Standard SingleSwab Culture Method, by Using Rigorous Gold Standard (“RGS”; Multiple Sample Swab Culture plus BrothEnhanced Pledget Culture) as the Gold StandardIn a hospital clinical lab field evaluation, two swabs (A and B) were collected from each of 302 patientspresenting with pharyngitis. Swabs were held in transport tubes with Stuart’s modified transport mediumuntil testing. Swabs A and B from each patient were inoculated on separate selective sheep blood agarplates. One swab (Swab A) was then tested by the OSOM Ultra Strep A Test and the other swab (SwabB) was tested by the Strep A OIA Max Test. Plates were incubated for 24 – 48 hours at 35˚C with 5 – 10%CO2. All pledgets from the transport tubes were placed aseptically in modified Todd Hewitt Broth (THB)for 16 – 24 hours at 35˚C with 5 – 10% CO2. After the initial incubation, the inoculated THB was sub-culturedon SXT agar plates and incubated for 24 – 48 hours at 35˚C with 5 – 10% CO2. All presumptive GAS colonieswere confirmed with commercially available Strep A test kits. A positive culture from either one of thetwo swabs or the pledget was considered a Rigorous Gold Standard (RGS) positive.Of 302 total patients sampled, 94 were found RGS positive and 208 were RGS negative, with a positiverate of 31.1%. The sensitivity of the OSOM Ultra Strep A Test, 92.6% (95% confidence interval (CI): 84.8 – 96.0%)was the same as the corresponding standard single swab culture, 92.6% (95% CI: 84.8 – 96.0%). In thesestudies, the two test methods’ sensitivities were not statistically different (p = 0.7811). The sensitivity of theOSOM Ultra Strep A Test was 92.6% and the sensitivity of the Strep A OIA Max Test was 75.5%, with p valueof 0.0021. The results are summarized below:Individual Test Results Compared to the RGS:Swab A - Culture vs RGSRGS + RGS - TotalCulture + 87 0 87Culture - 7 208 215Total 94 208 302Sensitivity: 87 / 94 = 92.6%Specificity: N/A aSwab B - Culture vs RGSRGS + RGS - TotalCulture + 82 0 82Culture - 12 208 220Total 94 208 302Sensitivity: 82 / 94 = 87.2%Specificity: N/A aSwab A - OSOM Ultra Strep A Test vs. RGSRGS + RGS - TotalUltra + 87 15 102Ultra - 7 193 200Total 94 208 302Sensitivity: 87 / 94 = 92.6%Specificity: 193 / 208 = 92.8%Swab B - Strep A OIA Max Test vs RGSRGS + RGS - TotalOIA + 71 6 77OIA - 23 202 225Total 94 208 302Sensitivity: 71 / 94 = 75.5%Specificity: 202 / 208 = 97.1%Summary of the Test Method Sensitivity and Specificity When Compared to the Rigorous Gold Standard:Test Method Sensitivity SpecificitySingle Swab Culture A (SSC A) 87 / 94 (92.6%) N/A aSingle Swab Cuture B (SSC B) 82 / 94 (87.2%) N/A aOSOM Ultra Strep A Test (Swab A) 87 / 94 (92.6%) 193 /208 (92.8%)Strep A OIA Max Test (Swab B) 71 / 94 (75.5%) 202 / 208 (97.1%)Statistical Analysis b for the Sensitivity of the Various Test Methods:Test Method Sensitivity pSSC A vs. SSC B 87 / 94 (92.6%) vs. 82 / 94 (87.2%) 0.3312OSOM Ultra vs. SSC A 87 / 94 (92.6%) vs. 87 / 94 (92.6%) 0.7811OIA Max vs. SSC B 71 / 94 (75.5%) vs. 82 / 94 (87.2%) 0.0581OSOM Ultra vs. OIA Max 87 / 94 (92.6%) vs. 71 / 94 (75.5%) 0.0021a. N/A, Not applicable, all culture positives are true-positive by definition.b. A statistical analysis using “The Difference Between Two Independent Proportions” by Fleiss (7) was used.

Comparison of the Performances of OSOM Ultra Strep A Test andStandard Single Swab Culture Method, by Using Combined Culture Standard(“CCS”; Single Swab Culture plus Broth Enhanced Pledget Culture) as the Gold StandardIn a field evaluation conducted by a clinical lab for a pediatric group practice, a total of 490 throatswabs were collected from patients presenting with pharyngitis. Swabs were held in transport tubeswith modified Stuart’s transport media until testing.Each swab was inoculated on a sheep blood agar plate, then tested by the OSOM Ultra Strep A Test.The plate methods were the same as previously described. All pledgets from the transport tubes werealso tested following the enhanced pledget culture method described previously. A positive culturefrom either the swab or the pledget was considered a Combined Culture Standard (CCS) positive.Of 490 total specimens, 164 were found CCS positive and 326 were CCS negative, with a positiverate of 33.5%. Of the 326 CCS negative specimens, 326 were also negative by the OSOM Ultra StrepA Test, for a specificity of 100% (95% CI: 98.5 – 100%). Of the 164 CCS positive specimens, 161 and 157were also positive by the standard single swab culture and the OSOM Ultra Strep A Test, respectively.These equal to sensitivities of 98.2% (95% CI: 94.3 – 99.2%) and 95.7% (95% CI: 91.1 – 97.7%) for the standardsingle swab culture and the OSOM Ultra Strep A Test, respectively. A statistical analysis comparing thesensitivity of the standard single swab culture and the OSOM Ultra Strep A Test, using “The DifferenceBetween Two Independent Proportions” by Fleiss (7) , showed these two methods were not statisticallydifferent (p = 0.3341).Sensitivity: 157 / 164 = 95.7%The results are summarized below:Test Results:Single Swab Culture vs. CCSOSOM Ultra Strep A Test vs. CCSCCS + CCS - TotalCCS + CCS - TotalCulture + 161 0 161Ultra + 157 0 157Culture - 3 326 329Ultra - 7 326 333Total 164 326 490Total 164 326 490Sensitivity: 161 / 164 = 98.2%Specificity: N/A a Specificity: 326 / 326 = 100%Sensitivity Analysis:Test Method Sensitivity SpecificitySIngle Swab Culture 161/164 (98.2%) N/A aOSOM Ultra Strep A Test 157/164 (95.7%) 326/326 (100%)p = 0.3341 N/A aa N/A, Not applicable, all culture positives are true-positive by definition.Evaluation of the Performance of OSOM Ultra Strep A Testby Using Standard Single Swab Culture Method as the Gold StandardIn a two site field evaluation, throat swabs were collected from patients presenting with pharyngitis. Eachswab was inoculated on a sheep blood agar plate, then tested by the OSOM Ultra Strep A Test. Plateswere incubated for 24 – 48 hours at 35˚C with 5 – 10% CO2. Presumptive GAS colonies were confirmed withcommercially available Strep A test kits. When the standard single swab culture method was used as thegold standard, the combined results from these two sites showed that the OSOM Ultra Strep A Test had asensitivity of 96.4% (239/248; 95% CI: 93.0 – 97.9%), a specificity of 96.3% (524/544; 95% CI: 94.3 – 97.5%), andan overall agreement of 96.3%. The results are summarized below:Culture DensityOSOM Ultra Strep A Results4+ (predominant grwoth) 89/89 (100%)3+ (>50 colonies) 90/91 (98.9%)2+ (11 – 50 colonies) 45/46 (97.8%)1+ (

TEST PROCEDUREAbsorbent End Result Window Handle EndSTEP 1Just before testing, squeeze the Extraction Reagent Bottleto crush the ampule inside. Note: The ampule must becrushed before proceeding to the next step.STEP 2Vigorously shake the Extraction ReagentBottle 3 – 5 times to mix the contents. Theliquid in the Extraction Reagent Bottleshould turn from pink to light yellow.6 dropsAdd 6 drops of the Extraction Reagentto the Test Tube.STEP 3Immediately put the swab into the Test Tube.10xVigorously mix the solution by rotating the swab forcefullyagainst the side of the Test Tube at least ten (10) times.Best results are obtained when the specimen is vigorouslyextracted in the solution.Let stand for 2 minutes.2 minSTEP 4Express as much liquid as possible from the swab bysqueezing the sides of the tube as the swab is withdrawn.Discard the swab.STEP 5Remove the Test Stick(s) from the container;re-cap the container immediately.Place the Absorbent End of the Test Stick into theextracted sample.STEP 6Read results at 5 minutes. Positive results may be readas soon as the red Control Line appears. Negative resultsmust be confirmed at 5 minutes.5 minResults are invalid after the read time.The use of a timer is recommended.

OSOMÃ‚Â® Ultra Strep A Test - Sekisui Diagnostics

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