Launching at MMC - Aspergillus Galactomannan EIA -

“Galactomannan Screening for the Early Diagnosis of Invasive Aspergillosis”

Dr. Vilma M. Co / Dr. Demetrio Valle

• Pledge of Support – Pfizer / Lifeline

• Message of Acceptance – Makati Medical Center

• Ceremonial MOA Signing

...........................Refreshments……………………….

Aspergillus

• fungus (or mold) that is common in the environment – soil– plants and in decaying plant

matter– household dust– building materials– spices & some food items.

Different types of Aspergillus

• Aspergillus fumigatus

• Aspergillus flavus

• Aspergillus terreus

• Aspergillus nidulans

• Aspergillus niger

Aspergillosis

1. allergic bronchopulmonary aspergillosis (also called ABPA)

- a condition where the fungus causes allergic respiratory symptoms, such as wheezing and coughing, but does not actually invade and destroy tissue.

2. Invasive Aspergillosis

- a disease that usually affects people with immune system problems.

- the fungus invades and damages tissues in the body.

- most commonly affects the lungs, but can also cause infection in many other organs & can spread throughout the body.

Aspergillosis

High-risk Patients

• Invasive aspergillosis generally affects

immunocompromised patients– bone marrow transplant or solid organ transplant, – people who are taking high doses of corticosteroids, – people getting chemotherapy for cancers such as leukemia. – persons with advanced HIV infection

Mode of Transmission

• Inhalation of Aspergillus spores (i.e., in a very dusty environment) can lead to infection.

• Studies have shown that invasive aspergillosis can occur during building renovation or construction.

• Outbreaks of Aspergillus skin infections have been traced to contaminated biomedical devices.

Symptoms of Aspergillosis:

1. respiratory symptoms like wheezing, coughing and even fever

2. allergic sinusitis/bloody sputum

3. aspergilloma, or a “fungus ball” in the lung or other organs.

• Lung aspergillomas usually occur in people

with other forms of lung disease, like emphysema or a history of TB.

Invasive Aspergillosis

• fever, chest pain, cough, and shortness of breath.

• When invasive aspergillosis spreads outside of the lungs, it can affect almost any organ in the body, including the brain.

Incubation Period

• Incubation time varies depending on host factors & exposure characteristics.

Diagnosis of Aspergillus infection

• risk factors, symptoms, & P.E. findings

• chest x-ray or CT scan of the lungs.

• fungal culture of samples of respiratory secretions or affected tissues

• biopsies of affected tissue

• newer tests that can help monitor for invasive aspergillosis in high-risk persons who are severely immunocompromised

Aspergillus Galactomannan EIA CLINICAL UTILITY

• used in conjunction with other diagnostic procedures to aid in the diagnosis of Invasive Aspergillosis. – microbiological culture – histological examination of biopsy specimens– radiographic evidence

Screening high-risk patients with PlateliaTM Aspergillus EIA, twice-weekly, provides early diagnosis of IA.

Recent publications: GM Ag was positive 6-10 days before onset of clinical signs GM positivity preceded positivity of CT-Scan or culture by >1 week PlateliaTM Aspergillus EIA was most sensitive (compared to RT-PCR and -glucan) at predicting the diagnosis of IA in patients with hematologic disorder.

Screening & Diagnosing IA in High-Risk Patients KEY BENEFITS :

Comparison to Other Diagnostic Methods :

Diagnostic Method Sensitivity SpecificityChest Radiograph 94% 60%

CT-Scan (any abnormality) 78% 7%

CT-Scan (halo sign) 28% 93%

Culture (BAL) 50% 92%

GM EIA :

Single sample 1.5

2 consecutive samples ≥ 1.5

94%

94%

85%

99%

J.Maertens JID 2002

Screening and Diagnosing IA in High-Risk patients

Treatment of Invasive Aspergillosis

• Voriconazole is currently first-line treatment for invasive aspergillosis.

• itraconazole, lipid amphotericin formulations, caspofungin, micafungin, and posaconazole

• Whenever possible, immunosuppressive medications should be discontinued or decreased.

Prevention

• avoidance of dusty environments and activities where dust exposure is likely (such as construction zones)

• wearing N95 masks in dusty environments • avoidance of activities such as gardening• air quality improvement measures such as HEPA

filtration may be used in healthcare settings• prophylactic antifungal medication in some

circumstances 

Platelia Aspergillus EIA and Diagnosis of IA

ELISA SETUPELISA SETUP

WASHER

INCUBATOR READER

PLATELIAPLATELIATMTM AspergillusAspergillus EIA and EIA and DIAGNOSIS of IADIAGNOSIS of IA

PROCEDURE

• immunoenzymatic sandwich microplate assay for the detection of Aspergillus galactomannan antigen

• adult and pediatric serum samples

• uses EBA-2 monoclonal antibodies which detect Aspergillus galactomannan.

For maximum sensitivity, the test should be performed at least twice-weekly during hospitalization. For all positive patients, it is recommended that a new aliquot of the same sample be repeated as well as collection of a new sample from the patient.

According to the EORTC/MSG criteria, two consecutive positive results are required for classification as true positive. In daily practice, it is important that physicians submit a follow-up specimen upon receipt of the initial positive result, ideally before initiating antifungal therapy to achieve the highest specificity using the test.

Screening & Diagnosing IA in High-Risk patients

SPECIMEN TYPE & SPECIMEN HANDLING

• Serum: • Collect 3 to 5 ml blood specimen in a serum

separator tube (SST) without anti-coagulants. • Allow specimen to clot, then centrifuge specimen

within 2 hours of draw to pellet cells below the gel. • Minimum volume of 1.0 ml serum following

centrifugation is required. • Specimen should be stored at 2 to 8°C or frozen in

a non-self-defrosting freezer & shipped with frozen gel packs or dry ice for overnight delivery

• BAL:

• 1 to 3 ml collected in a sterile, screw-cap tube;

• specimen should be stored at 2 to 8°C or frozen in a non-self-defrosting freezer

• shipped with frozen gel packs or dry ice for overnight delivery

SPECIMEN TYPE & SPECIMEN HANDLING

CAUSES FOR REJECTION of specimen

• Lipemic, icteric, or hemolyzed specimens.

• Specimens that have been stored at ambient temperature.

• Specimens that have been stored at 2 to 8°C for >5 days.

• If storage longer than 5 days is needed, samples should be frozen at -70°C.

ASSAY RANGE

• The reference range is an index of <0.5.• Numerical index values will be reported. • Patients with an index of >0.5 are

considered to be positive for galactomannan antigen.

• Patients with an index of <0.5 are considered to be negative for galactomannan antigen.

ASSAY LIMITATIONS

• A negative test result cannot rule out the diagnosis of Invasive Aspergillosis.

• Patients at risk for Invasive Aspergillosis should be tested twice per week.

• If a positive result is obtained, a second specimen should be collected and sent for testing immediately.

False-positive galactomannan test results

• patients receiving piperacillin/tazobactam; interpret results in these patients with caution & confirm w/ other diagnostic methods.

• Patients with intestinal mucositis caused by chemotherapy / irradiation, which allows for extra absorption of dietary galactomannan.

• patients receiving Plasmalyte for IV hydration or if Plasmalyte is used for BAL collection.

TURNAROUND TIME

• Same day (within 8 to12 hours of specimen receipt)

Thank you!