QUICK ANSWERS
TO COMMON QUESTIONS

Find answers below to frequently asked questions. If you don’t find what you are looking for, please contact us directly by email or phone.

 
GENERAL

Contact Customer Care or complete the supply request form online here. Inform the team if the supplies need to go out right away. The order will be sent within 24 hours.

Your office may choose to receive reports through fax, mail, or our simple-to-use results portal. Your office may choose to change the format in which you receive the report at any time. Contact Customer Care with your office preference.

You may contact Customer Care, and we will put you in touch with our technical service team.

GUIDANCE FOR UROLOGY

Unless the patient is immunosuppressed or pregnant, the presence of bacteria alone in the absence of symptoms should not trigger the ordering of a Guidance test. Asymptomatic bacteriuria is a common finding particularly in the elderly and should not be treated unless symptoms develop.

Serial dilutions were used to compare CFU/mL and cells/mL during our validation studies. We found that the CFU/mL and cells/mL units were similar for most organisms, with the molecular assay illustrating a longer and more accurate linear range. In many cases it was found that culture misrepresented the number of CFUs measured and at different times both understated and overstated the actual number of bacteria present. The threshold for clinical significance remains the same for both technologies and reporting units.

Guidance detects organisms that are often missed by culture. This does not suggest that these are rare organisms with relatively low bacterial loads. In fact, most uropathogens found via Guidance have a bacterial count of >100,000 cells/mL. Studies show that standard urine techniques fail to spot a high proportion (67%) of uropathogens that may be clinically relevant.1 Other independent studies have shown that molecular identification of organisms acquired through transurethral catheter (TUC) or subpubic aspirate (SPA) are highly similar. Those acquired by voided urine were also similar, except the sample contained bacteria associated with vulvo-vaginal contamination. Of the microbes suspected to be vulvo-vaginal contaminates, only one of the detected species aligns with the Guidance profile. Guidance also quantitates organisms so that physicians can treat the organisms that are above a certain threshold for patients with symptoms of a UTI.15

It is the physician’s prerogative to determine when and how to treat a patient based on clinical symptoms and the presence of bacteria, virus, or yeast in the urine.

Internal data shows that 67% of cases with a bacterial load of 10,000 cells/mL or greater are typically at 100,000 cells/mL and higher. Contamination would typically result in a lower bacterial load.

Portions of the Guidance test results are molecular in nature. Organisms are identified by the assay as present in the sample as long as DNA from those organisms is present and intact, regardless of the viability of the organismal cells.

Sensitivity/Resistance testing is performed when any one of the pathogens is at a concentration of or above 10,000 cells/mL. Additionally, the sensitivity/resistance portion of the report requires viable organisms. If the organismal cells are non-viable or the pathogenic organism concentration is below 10,000 cells/mL, the laboratory report will generate a list of antibiotics that may inhibit all the pathogenic organisms based on clinical studies alone.

Both traditional susceptibility and the Pathnostics proprietary mixed antibiotic susceptibility tests are culture-based. Traditional culture pulls a single colony from a plate and tests it against various antibiotics to determine sensitivity. The Pathnostics patented methodology differs from traditional methods in that it determines the susceptibility of the entire population of identified pathogenic organisms simultaneously against each antibiotic.

The Pathnostics patented pooled population methodology grows all identified uropathogenic organisms together at one time and tests them against each relevant antibiotic. Internal studies have shown that the MIC levels change when organisms are presented with antibiotics in a mixed format rather than as individuals.

Additional information to consider: Traditional methods determine the antibiotic resistance of a single pathogen. Studies have shown that UTIs may be caused by polymicrobial infections (multiple pathogens). These polymicrobial infections have increased frequency of antibiotic resistance due to mutualism between the different pathogens. Pathnostics’ patented methodology grows all the uropathogenic organisms together at one time and tests all the organisms against each relevant antibiotic.

Portions of the Guidance test results are molecular in nature. If intact DNA from one or more of the 42 organisms targeted by the test are not found in the sample, the report will indicate “No Uropathogenic Organisms Detected.”

Sensitivity/Resistance testing is performed when the cellular concentration is at or above 10,000 cells/mL. Therefore, in a case where uropathogenic organisms are not detected, susceptibility testing is not performed.

Historically, UTIs have been defined by the growth of a single pathogen at a density threshold of 100,000 CFU/mL on a culture plate. This threshold was established by E.H. Kass in the 1950s. Even then, researchers realized that using 100,000 CFU/mL threshold levels would result in the misdiagnosis of patients who have true UTIs with lower bacterial counts.

In 1982, Stamm et al. showed that the 100,000 CFU/mL threshold caused 49% women to be misdiagnosed as negative for a UTI and therefore established a new threshold of 100 CFU/mL for symptomatic patients.16,17

It is the physician’s prerogative to determine when and how to treat a patient based on clinical symptoms and the presence of bacteria or yeast in the urine. It should be noted that the report is not intended to be prescriptive for patients, and that appropriate medical judgement should be exercised by the attending physician before prescribing a course of treatment.

The antibiotic susceptibility of bacteria is derived through a patent pending high-throughput spectrophotometric assay. Regardless of the number of causative agents, the assay discerns the list of antibiotics that will resolve the infection.

We essentially grow all the organisms at one time in each well of a 96-well plate, incubate 1 drug in a well, and then measure growth. No growth = susceptibility or sensitivity. Growth = resistance.

Yes, blood does not interfere with the PCR reaction or the ABR.

GUIDANCE FOR HPV

In reviewing the test’s accuracy, there are several factors that both physicians and scientists assess. These include the following:

Sensitivity (also known as the true positive rate): Gauges the proportion of positive results that are correctly determined as such. For example, the percentage of sick people who are correctly identified as being sick.

Specificity (also known as the true negative rate): Gauges the proportion of negatives that are correctly determined as such. For example, the proportion of healthy people who are correctly identified as not being sick.

PPV and NPV (Positive Predictive Value and Negative Predictive Value): The positive and negative predictive values (PPV and NPV respectively) are the percentages of positive and negative results that are truly positive and truly negative, respectively. The PPV and NPV explain the effectiveness of a diagnostic test. The higher the percentage, the greater likelihood that there is to suggest that the diagnostic test is accurate.

MARKER(S) SENSITIVITY SPECIFICITY PPV NPV
High-Risk HPV 94.0% 25.6% 2.0% 99.2%
p16 + Ki-67 89.4% 82.1% 54.7% 95.1%
TERCcMyc 78.0% 95.3% 89.7% 97.0%

A Pap smear typically consists of a pathologist reviewing the shape of the cells under the microscope. Cells, prior to transforming into cancer, undergo predictable molecular changes that are not visible through the microscope unless special stains are applied to the cell. The additional markers, such as p16, Ki-67, TERC, and cMyc allow the pathologists to visualize the expression levels or molecular amplification of these cancer-producing genes.

A small percentage of high-risk HPV-positive patients will progress to have cervical cancer. Without analysis of the markers, it is impossible to immediately assess the risks of cervical cancer, leaving you uncertain about whether you require aggressive monitoring or you should wait and let the infection resolve on its own. The additional markers allow your physician to create better outcomes by confidently determining if you truly require more aggressive treatment options.

Patients who would most benefit from this test are borderline cases. Also, patients who have ASCUS, LSIL, or HPV are ideal candidates for this type of test.

Yes, clients may obtain a preliminary report for the Pap test by either contacting Customer Care or by requesting that their preliminary results are sent to the office on a regular basis.

Acceptable and preferred Pap samples should be collected from the cervix.

Initial results are reported out within 72 hours after sample arrival in the lab. If the Pap sample is ASCUS, LSIL, positive or HPV-positive but has normal cells, the Guidance HPV will perform testing on additional markers. The complete result is reported out within 72 hours after the initial Pap results.

It is best to send the sample to the lab the same day it is collected. We supply ThinPrep PreservCyt jars, which stabilize the sample for up to 6 weeks at room temperature. Therefore, it is important to ensure the sample arrives within 6 weeks of being collected.

Image
Guidance points the way to swift diagnosis and therapy options that work
the first time for recurrent UTIs, prostatitis, and much more.