Asymptomatic and Subclinical Mpox: An Association With Modified Vaccinia Ankara Vaccine.

BACKGROUND: How often mpox causes asymptomatic infections, particularly among persons who have received the Modified Vaccinia Ankara (MVA) vaccine, is unknown. METHODS: We performed mpox polymerase chain reaction testing on rectal and pharyngeal specimens collected from symptomatic and asymptomatic patients at a sexual health clinic in Seattle, WA, between May 2022 and May 2023. Analyses evaluated the prevalence of asymptomatic or subclinical infection and, among persons with polymerase chain reaction-positive tests, the association of MVA vaccination status with the symptomatic infection. RESULTS: The study population included 1663 persons tested for mpox during 2353 clinic visits. Ninety-three percent of study participants were cisgender men and 96% were men who have sex with men. A total of 198 symptomatic patients (30%) had a first mpox-positive test during 664 visits. Eighteen patients (1.1%) tested during 1689 visits had asymptomatic or subclinical mpox based on a positive rectal or pharyngeal test done in the absence of testing done because of clinical suspicion for mpox. Fourteen (78%) of 18 persons with asymptomatic/subclinical mpox and 53 (26%) of 198 persons with symptomatic mpox had received at least 1 dose of the MVA vaccine ( P < 0.0001). Controlling for calendar month, study subjects who received 1 and 2 doses of MVA vaccine were 4.4 (95% confidence interval, 1.3-15) and 11.9 (3.6-40) times more likely to have asymptomatic versus symptomatic mpox, respectively, than persons who were unvaccinated. CONCLUSIONS: Asymptomatic mpox is uncommon. Modified Vaccinia Ankara vaccination is associated with an asymptomatic/subclinical infection among persons with mpox.

Analytical Performance Characteristics of a New Transcription-Mediated Amplification Assay for Treponema pallidum.

This study evaluated the performance characteristics of a new research-use-only transcription-mediated amplification (TMA) assay for the detection of rRNA from Treponema pallidum. Analytical sensitivity determined using dark-field microscopy-quantitated T. pallidum was 1.4 organisms/ml (95% confidence interval [CI], 0.7 to 6.33 organisms/ml). Dilution of in vitro-transcribed (IVT) T. pallidum RNA in Aptima sample transport medium (STM) yielded 100% positivity (n = 3) at 10 copies/ml (4 copies/reaction). Analytical specificity testing of nontarget microorganisms (n = 59), including the closely related nonsyphilis treponemes Treponema denticola and Treponema phagedenis, yielded 0% positivity. TMA testing of mucosal swab specimens collected from men who have sex with men (MSM) attending a sexually transmitted disease clinic yielded 1.8% (17/944) positive results. A collection of 56 serum specimens obtained from a separate cohort of patients with known rapid plasma reagin (RPR) statuses and clinical diagnoses of syphilis was 19.6% (11/56) TMA positive overall and 29.7% (11/37) positive among subjects with syphilis diagnoses, including 8 (36.3%) of 22 persons with primary or secondary syphilis, 2 (20%) of 10 persons with early latent syphilis, and 1 (20%) of 5 persons with late latent or unstaged syphilis. None (0%) of the 18 RPR-positive sera from patients with histories of treated syphilis were TMA positive. These results show that TMA is an analytically sensitive and specific method for the detection of T. pallidum rRNA and is compatible with serum specimens in addition to pharyngeal and rectal mucocutaneous swab specimens. Automated real-time TMA testing for T. pallidum may be useful as an adjunctive method with serology for screening and diagnostic testing of selected patient populations for syphilis.

Treponema pallidum Nucleic Acid Amplification Testing To Augment Syphilis Screening among Men Who Have Sex with Men.

Syphilis rates in much of the world are now at their highest levels in almost three decades, and new approaches to controlling syphilis, including diagnostic tests with shorter window periods, are urgently needed. We compared the sensitivity of syphilis serological testing using the rapid plasma reagin (RPR) test with that of the combination of serological testing and an experimental 23S rRNA Treponema pallidum real-time transcription-mediated amplification (TMA) assay performed on rectal and pharyngeal mucosal swabs. T. pallidum PCR assays for the tpp47 gene were performed on all TMA-positive specimens, as well as specimens from 20 randomly selected TMA-negative men. A total of 545 men who have sex with men (MSM) who were seen in a sexually transmitted disease clinic provided 506 pharyngeal specimens and 410 rectal specimens with valid TMA results. Twenty-two men (4%) were diagnosed with syphilis on the basis of positive RPR test results and clinical diagnoses, including 3 men with primary infections, 8 with secondary syphilis, 9 with early latent syphilis, 1 with late latent syphilis, and 1 with an unstaged infection. Two additional men were diagnosed based on positive rectal mucosal TMA assay results alone, and both also tested positive by PCR assay. At least 1 specimen was TMA positive for 12 of 24 men with syphilis (sensitivity, 50% [95% confidence interval [CI], 29 to 71%]). RPR testing and clinical diagnosis were 92% sensitive (95% CI, 73 to 99%) in identifying infected men. Combining mucosal TMA testing and serological testing may increase the sensitivity of syphilis screening in high-risk populations.

Evaluation of a transcription mediated amplification assay for detection of herpes simplex virus types 1 and 2 mRNA in clinical specimens.

BACKGROUND: Herpes simplex viruses (HSV) are double-stranded DNA human herpesviruses (HHVs) that have the capacity to cause significant morbidity and mortality in humans. Like HHV5 (Cytomegalovirus) and HHV8 (Kaposi's sarcoma virus), HSV type 1 (HSV-1), and HSV type 2 (HSV-2) (HHV1, HHV2) selectively package certain viral messenger RNAs inside mature virions, as well as expressing those mRNAs in infected cells. OBJECTIVES: To evaluate the clinical and analytical performance of Aptima HSV 1&2 assay (AHSV), a newly developed automated real time transcription-mediated amplification (TMA) nucleic acid amplification test (NAAT) for HSV-1 and 2 UL42 mRNAs, compared to viral culture and HSV DNA NAAT. STUDY DESIGN: Cutaneous and mucocutaneous lesion swab specimens from a population of symptomatic female and male subjects attending a U.S. public health clinic (n=758) were evaluated by shell vial culture with fluorescent antibody staining for HSV-1 and 2. Specimens were then tested with AHSV for HSV-1 and 2 on the Panther instrument. Specimens from subjects with discordant culture-TMA paired results were tested using an FDA-cleared test for HSV-1 and 2 viral DNA. Analytical performance of AHSV was evaluated using test panels consisting of laboratory strains of HSV-1 and 2 and a variety of non-target human DNA viruses. RESULTS: Compared to culture, AHSV was sensitive and specific for detection of HSV-1 and 2 in patient lesion swab specimens, exhibiting clinical sensitivities of 98.2% (95% CI: 92.9-99.7) and 99.4% (95% CI: 96.0-99.9), respectively. Addition of HSV DNA NAAT discordant resolution testing results to culture results improved AHSV sensitivity for HSV-1 and 2-99.2% (95% CI: 94.7-99.9) and 100% (95% CI: 97.5-100), respectively. Clinical specificity of AHSV for HSV-1 and 2 detection was 97.8% (95% CI: 96.3-98.8) and 94.5% (95% CI: 92.2-96.1), respectively, compared to culture; and 99.5% (95% CI: 98.5-99.9) and 99.5% (95% CI: 98.3-99.7), respectively, compared to culture with discordant resolution. Analytical sensitivity (95% limit of detection) of AHSV for HSV-1 (McIntyre strain) was 28.9 TCID50/mL (95% FL: 23.4-37.9), and 0.54 TCID50/mL (95% FL: 0.42-0.75) for HSV-2 (MS strain). AHSV did not cross-react with laboratory strains of HHV-3, HHV-4, HHV-5, HHV-6, and four other non-HHV human DNA viruses. CONCLUSIONS: Real time transcription-mediated amplification NAAT for HSV viral mRNA is a sensitive and specific method for detection of herpes simplex virus infection in symptomatic patients.

Performance of Determine Combo and other point-of-care HIV tests among Seattle MSM.

BACKGROUND AND OBJECTIVE: The rapid test study was a real-time comparison of point-of-care (POC) HIV tests to determine their abilities to detect early HIV infection. STUDY DESIGN: Men and transgender persons reporting sex with men in the prior year were recruited at the Public Health-Seattle & King County STD Clinic, Gay City Health Project, and University of Washington Primary Infection Clinic. Study tests included the OraQuick ADVANCE Rapid HIV-1/2 Antibody Test performed on oral fluids and tests performed on fingerstick whole blood specimens including OraQuick, Uni-Gold Recombigen HIV test, Determine HIV-1/2 Ag/Ab Combo, and INSTI HIV-1 Rapid Antibody Test. Specimens from subjects with negative results were sent for EIA and nucleic acid amplification testing. McNemar's exact tests compared the numbers of HIV-infected subjects detected. RESULTS: Between February 2010 and August 2014, there were 3438 study visits. Twenty-four subjects had discordant POC results with at least one reactive and one non-reactive test, including one subject with a reactive Determine p24 antigen. OraQuick performed on oral fluids identified fewer persons compared to all fingerstick tests. OraQuick performed on fingerstick whole blood detected fewer persons compared to the Determine Combo antibody component (p=.008) and Combo overall (p=.004), and there was a trend when compared to INSTI (p=.06). The Determine Combo specificity was 98.99%. CONCLUSIONS: As reported by others, Determine Combo underperforms compared to laboratory-based testing, but it did detect one acute infection. If these results are validated, the specificity of Determine Combo may limit its usefulness in populations with lower HIV incidence.

Relative accuracy of serum, whole blood, and oral fluid HIV tests among Seattle men who have sex with men.

BACKGROUND: Point-of-care (POC) rapid HIV tests have sensitivity during the "window period" comparable only to earliest generation EIAs. To date, it is unclear whether any POC test performs significantly better than others. OBJECTIVE: Compare abilities of POC tests to detect early infection in real time. STUDY DESIGN: Men who have sex with men (MSM) were recruited into a prospective, cross-sectional study at two HIV testing sites and a research clinic. Procedures compared four POC tests: one performed on oral fluids and three on fingerstick whole blood specimens. Specimens from participants with negative POC results were tested by EIA and pooled nucleic acid amplification testing (NAAT). McNemar's exact tests compared numbers of HIV-infected participants detected. RESULTS: Between February 2010 and May 2013, 104 men tested HIV-positive during 2479 visits. Eighty-two participants had concordant reactive POC results, 3 participants had concordant non-reactive POC tests but reactive EIAs, and 8 participants had acute infection. Of 12 participants with discordant POC results, OraQuick ADVANCE Rapid HIV-1/2 Antibody Test performed on oral fluids identified fewer infections than OraQuick performed on fingerstick (p = .005), Uni-Gold Recombigen HIV test (p = .01), and determine HIV-1/2 Ag/Ab combo (p = .005). CONCLUSIONS: These data confirm that oral fluid POC testing detects fewer infections than other methods and is best reserved for circumstances precluding fingerstick or venipuncture. Regardless of specimen type, POC tests failed to identify many HIV-infected MSM in Seattle. In populations with high HIV incidence, the currently approved POC antibody tests are inadequate unless supplemented with p24 antigen tests or NAAT.

Performance of an alternative HIV diagnostic algorithm using the ARCHITECT HIV Ag/Ab Combo assay and potential utility of sample-to-cutoff ratio to discriminate primary from established infection.

BACKGROUND: The ARCHITECT HIV Ag/Ab Combo assay has a wide dynamic range for determining the sample-to-cutoff ratio (S/CO) values compared to other diagnostic HIV antibody assays. OBJECTIVES: Determine the performance of an HIV testing algorithm that uses the ARCHITECT combo assay in the clinical setting and explore the utility of the signal-to-cutoff (S/CO) ratio to predict acute HIV-1 infection status. STUDY DESIGN: A retrospective analysis of clinical samples from a hospital and referral population screened for HIV-1 infection between May 2011 and March 2013. Repeatedly reactive samples were tested using the Multispot HIV-1/HIV-2 rapid test and depending on that result, confirmatory orthogonal testing used the Western blot (WB) for HIV-1, Immunoblot for HIV-2 and nucleic acid amplification testing (NAAT) for HIV RNA. RESULTS: A total of 21,317 test results were evaluated of which 509 were ARCHITECT repeatedly reactive; of these, 422 were Multispot-reactive only for HIV-1 (413 WB-positive; 9 indeterminate), 4 were Multispot-reactive for both HIV-1 and HIV-2 (one HIV-2 immunoblot-positive with 17 HIV-2 RNA copies/mL) and 83 were Multispot-non-reactive of which 15 were HIV-1 RNA positive and represented acute HIV-1 infection. There was an association among the ARCHITECT S/CO (median; IQR) values for antibody-negative (0.14; 0.11-0.16), acute infection (33; 2.1-76) and established HIV-1 infection (794; 494-1,029) (Kruskal-Wallis, p<0.0001). CONCLUSIONS: The ARCHITECT combo assay with Multispot confirmation and reserved use of HIV-1 WB, HIV-2 Immunoblot and HIV NAAT for Multispot dual HIV-1/2 infection, and NAAT alone for Multispot-negative specimens, had a suitable test performance for detecting acute and established HIV infection.

Performance evaluation of the Bio-Rad Laboratories GS HIV Combo Ag/Ab EIA, a 4th generation HIV assay for the simultaneous detection of HIV p24 antigen and antibodies to HIV-1 (groups M and O) and HIV-2 in human serum or plasma.

BACKGROUND: A multi-center study was conducted to evaluate the Bio-Rad GS HIV Combo Ag/Ab EIA, a 4th generation HIV-1/HIV-2 assay for the simultaneous detection of HIV p24 antigen and antibodies to HIV-1 (groups M and O) and HIV-2 in human serum or plasma in adult and pediatric populations. OBJECTIVES: The objectives of the study were to assess assay performance for the detection of acute HIV infections; sensitivity in known HIV positive samples; percent agreement with HIV status; specificity in low and high risk individuals of unknown HIV status; and to compare assay performance to a 3rd generation HIV assay. STUDY DESIGN: The evaluation included testing 9150 samples at four U.S. clinical trial sites, using three kit lots. Unlinked samples were from routine testing, repositories or purchased from vendors. RESULTS: GS HIV Combo Ag/Ab EIA detection in samples from individuals in two separate populations with acute HIV infection was 95.2% (20/21) and 86.4% (38/44). Sensitivity was 100% (1603/1603) in known antibody positive [HIV-1 Groups M and O, and HIV-2] samples. HIV p24 antigen detection was 100% (53/53) in HIV-1 culture supernatants. HIV-1 seroconversion panel detection improved by a range of 0-20 days compared to a 3rd generation HIV test. Specificity was 99.9% (5989/5996) in low risk, 99.9% (959/960) in high risk and 100% (100/100) in pediatric populations. CONCLUSION: The GS HIV Combo Ag/Ab EIA significantly reduced the diagnostic window when compared to the 3rd generation screening assay, enabling earlier diagnosis of HIV infection. The performance parameters of the Bio-Rad GS HIV Combo Ag/Ab EIA are well suited for use in HIV diagnostic settings.

Health care disparities in the acute management of venous thromboembolism based on insurance status in the U.S.

Acute venous thromboembolism (VTE) is common, costly, and potentially lethal. Therapeutic anticoagulation requires timely, closely monitored medical follow-up. If ineffective, clinical outcomes worsen and resource utilization increases. This risk may be magnified in uninsured patients. This study examined VTE care in hospital patients and investigated differences based on insurance status. We performed a retrospective chart review on medical VTE patients at an academic teaching hospital between December 1, 2007 and April 30, 2009. We reviewed medical records for demographics, insurance, admission status, length of stay (LOS), and 30-day Emergency Department (ED) recidivism and hospital readmission. Measured outcomes were analyzed based on payer source. We identified 234 medical VTE patients; 67 patients were uninsured (28.6%). 106 patients (45.3%) presented with deep vein thrombosis only. Most VTE patients were admitted to the hospital (171; 73.1%), including all 128 pulmonary embolism patients. Admitted uninsured patients averaged a LOS of 5.5 versus 3.7 days for insured (P = 0.03), with ED recidivism rates of 26.1 versus 11.3%, respectively (P = 0.02). Average cost for all VTE care in uninsured patients was $12,297 versus $7,758 for insured patients (P = 0.04). This study identified disparities in medical care and resource utilization for medical VTE patients based on insurance. Uninsured VTE patients were hospitalized nearly two additional days and were more than two times as likely to return to the ED within 30 days compared to insured patients. Additional research is needed to explain these disparities, and to explore system improvements for the uninsured VTE patient.

Shedding of pandemic (H1N1) 2009 virus among health care personnel, Seattle, Washington, USA.

The Centers for Disease Control and Prevention (CDC) recommends that health care personnel (HCP) infected with pandemic influenza (H1N1) 2009 virus not work until 24 hours after fever subsides without the use of antipyretics. During an influenza outbreak, we examined the association between viral shedding and fever among infected HCP. Participants recorded temperatures daily and provided nasal wash specimens for 2 weeks after symptom onset. Specimens were tested by using PCR and culture. When they met CDC criteria for returning to work, 12 of 16 HCP (75%) (95% confidence interval 48%-93%) had virus detected by PCR, and 9 (56%) (95% confidence interval 30%-80%) had virus detected by culture. Fever was not associated with shedding duration (p = 0.65). HCP might shed virus even when meeting CDC exclusion guidelines. Further research is needed to clarify the association between viral shedding, symptoms, and infectiousness.

HIV testing in a high-incidence population: is antibody testing alone good enough?

BACKGROUND: The Centers for Disease Control and Prevention recently recommended the expansion of human immunodeficiency virus (HIV) antibody testing. However, antibody tests have longer "window periods" after HIV acquisition than do nucleic acid amplification tests (NAATs). METHODS: Public Health-Seattle & King County offered HIV antibody testing to men who have sex with men (MSM) using the OraQuick Advance Rapid HIV-1/2 Antibody Test (OraQuick; OraSure Technologies) on oral fluid or finger-stick blood specimens or using a first- or second-generation enzyme immunoassay. The enzyme immunoassay was also used to confirm reactive rapid test results and to screen specimens from OraQuick-negative MSM prior to pooling for HIV NAAT. Serum specimens obtained from subsets of HIV-infected persons were retrospectively evaluated by use of other HIV tests, including a fourth-generation antigen-antibody combination assay. RESULTS: From September 2003 through June 2008, a total of 328 (2.3%) of 14,005 specimens were HIV antibody positive, and 36 (0.3%) of 13,677 antibody-negative specimens were NAAT positive (indicating acute HIV infection). Among 6811 specimens obtained from MSM who were initially screened by rapid testing, OraQuick detected only 153 (91%) of 169 antibody-positive MSM and 80% of the 192 HIV-infected MSM detected by the HIV NAAT program. HIV was detected in serum samples obtained from 15 of 16 MSM with acute HIV infection that were retrospectively tested using the antigen-antibody combination assay. CONCLUSIONS: OraQuick may be less sensitive than enzyme immunoassays during early HIV infection. NAAT should be integrated into HIV testing programs that serve populations that undergo frequent testing and that have high rates of HIV acquisition, particularly if rapid HIV antibody testing is employed. Antigen-antibody combination assays may be a reasonably sensitive alternative to HIV NAAT.

Screening for acute HIV infection: lessons learned.

Human immunodeficiency virus (HIV) nucleic acid testing is increasingly being used by researchers and public health screening programs to identify highly infectious, HIV antibody-negative individuals with acute HIV infection. We present cases to illustrate unusual instances of acute HIV screening, which include "window period" testing and the discovery of low-level HIV RNA.

A new algorithm for deduction of hepatitis B surface antigen subtype determinants from the amino acid sequence.

OBJECTIVE: We have reexamined hepatitis B virus subtypes to determine the role of specific HBsAg amino acids in serologic reactivity because of problematic genotype/subtype associations seen in a set of geographically diverse serum specimens. METHODS: We obtained DNA sequences for 491 HBsAg-positive specimens from geographically distinct locations, determined their genotypes through phylogenetic analysis, and subtyped the specimens using an algorithm derived from published data on the molecular basis of HBsAg subtype reactivity. Problematic samples were subtyped serologically to resolve conflicts based on the amino acid sequence alone. RESULTS: Three isolates were found to have unusual genotype/subtype associations. Examination of the isolates' amino acid sequences suggested amino acid positions 122, 127, 140, 159 and 160 can be used to determine subtype reactivity from HBsAg amino acid sequences, while position 134, previously thought to play a role, is no longer important. CONCLUSIONS: This re-examination of hepatitis B virus subtypes shows the involvement of amino acid positions 122, 127, 140, 159 and 160 in HBsAg reactivity. While d, y, and r reactivities are controlled by single amino acid changes, w reactivity is determined by positions 122, 127, 140, and 159.

Herpes simplex virus type 2 (HSV-2) Western blot confirmatory testing among men testing positive for HSV-2 using the focus enzyme-linked immunosorbent assay in a sexually transmitted disease clinic.

OBJECTIVE: The objective of this study was to define the positive predictive value (PPV) of the Focus herpes simplex virus type 2 (HSV-2) enzyme-linked immunosorbent assay (ELISA) in a low HSV-2 prevalence population and to develop a new test interpretation algorithm. METHODS: HSV-2 Western blots were performed on sera from male sexually transmitted disease clinic patients testing HSV-2 ELISA-positive and used to define a new class of indeterminate HSV-2 ELISA result. HSV-2 Western blots were then prospectively performed on sequential sera with indeterminate HSV-2 ELISAs. RESULTS: Ninety-one (84%) of 108 HSV-2 ELISA-positive sera tested HSV-2 Western blot-positive. Western blot positivity was more common in men without herpes simplex virus type 1 (HSV-1) antibody than in those with HSV-1 antibody (93% vs 76%, P = 0.02) and in men with a history or clinical evidence of genital lesions (88% vs 80%, P = 0.30). Selectively raising the ELISA index value defining HSV-2 positivity from >1.1 to >or=3.0 either among HSV-1-positive men or among those without a history or clinical evidence of genital lesions increased the PPV to >or=93%. Prospective evaluation of an algorithm incorporating HSV-1 serostatus found that 11 of 70 persons with indeterminate HSV-2 ELISAs were Western blot-positive. CONCLUSIONS: Clinicians should consider selectively using a higher index value to define Focus ELISA HSV-2 positivity based on either HSV-1 serostatus or clinical circumstances.

Targeted screening for primary HIV infection through pooled HIV-RNA testing in men who have sex with men.

HIV-RNA testing may identify individuals with primary HIV infection. Men who have sex with men (MSM) having HIV testing through Public Health, Seattle and King County were screened for primary infection through pooled RNA testing. Eighty-one out of 3525 specimens (2.3%) had detectable antibody and RNA, and seven out of 3439 antibody-negative specimens (0.2%) had HIV RNA. Targeted screening for primary infection through pooled RNA testing in MSM is a useful addition to HIV case finding.

Positive predictive value of Gen-Probe APTIMA Combo 2 testing for Neisseria gonorrhoeae in a population of women with low prevalence of N. gonorrhoeae infection.

We collected specimens from women who tested positive for Neisseria gonorrhoeae using the Gen-Probe APTIMA Combo 2 (AC2), and we performed confirmatory tests using a nucleic acid amplification test (NAAT) that targets alternate gonococcal nucleic acid sequences. Among 59,664 specimens, 280 (0.47%) had positive results using AC2; 265 of these specimens were tested using the confirmatory NAAT, of which 258 yielded positive results (positive predictive value, 97.4%; 95% confidence interval, 95.1%-98.8%). Routine confirmatory testing of specimens with positive AC2 gonorrhea test results is not indicated.

Evaluation of a public health Salmonella surveillance system in King County, Washington.

OBJECTIVES: Salmonella infection is the most common cause of foodborne bacterial outbreaks and deaths in the United States. The effectiveness of Salmonella surveillance for detecting outbreaks depends on timeliness of reporting. We evaluated the public health Salmonella surveillance system in King County, Washington, during an outbreak and at baseline. METHODS: We assessed the timeliness of the Salmonella surveillance system in King County using the Public Health-Seattle & King County Laboratory (County PHL) database from 1998 to 1999. We determined median days for key steps involved in the Salmonella identification and reporting process and the percentage of suspected Salmonella isolates confirmed. Time intervals for key steps during a Salmonella outbreak were compared to baseline surveillance. RESULTS: Of the 652 suspected Salmonella isolates sent to the County PHL from 22 clinical laboratories, 617 (94.6%) were confirmed as Salmonella. Salmonella confirmation rates improved from 1998 to 1999, and 41% of the submitting laboratories, contributing 32.4% of the isolates, had 100% confirmation rates for both years. The median total identification time during the outbreak did not differ significantly from baseline (13 days vs 17 days). The time interval for serotyping contributed most to the total identification time. CONCLUSIONS: King County's Salmonella surveillance system requires more than 2 weeks to confirm and report serotype results for Salmonella isolates. Variation in total identification time depends on serotyping time. A more detailed study of other surveillance systems may identify approaches to decrease total identification time.