Technical Bulletins

Technical Bulletins - announcements regarding test menu modifications and enhancements

TREPONEMA PALLIDUM AB (Syphilis) IgG and IgM, Serum

Topic:  TREPONEMA PALLIDUM AB (Syphilis) IgG and IgM, Serum Date: 6-30-2015

Test Name TREPONEMA PALLIDUM AB (Syphilis) IgG and IgM, Serum
Test Code TREP
Method EIA, Qualitative Enzyme Immunoassay
Changes Reverse Sequence Syphilis Screening will replace current RPR screening test
Specimen 1 mL SST serum 
Test Schedule Monday through Friday; Analytical time 1 day.

Change: Effective June 30, 2015, NorDx will start offering the new algorithm for reverse sequence syphilis screening based on the 2009 Laboratory Guidelines proposed by the Association of Public Health Laboratories Expert Consultation Meeting Summary Report, of 2009 in Atlanta, GA in association with the CDC. Please see attached testing algorithm and interpretation.

Interpretation:  
This new protocol consists of an initial anti-treponemal EIA screening test (Trep-Sure EIA). A negative result can exclude a diagnosis of syphilis except for incubating or early primary disease, while a positive or indeterminate result will be followed by a non-specific treponemal test (RPR, including dilutions), also performed by NorDx. If both the specific treponemal and non-treponemal tests are positive the diagnosis of syphilis is considered positive. If there are discrepancies between the two NorDx tests we will automatically reflex the specimen for a third treponemal specific antibody test,  TP-PA (Treponema pallidum – particle agglutination) performed at the HETL in Augusta ME.
If the TP-PA is positive the diagnosis of syphilis (past or present) is made. If the TP-PA test is negative, the initial EIA test can be considered as false positive and syphilis is unlikely; however, if the patient is at risk for syphilis, retesting in one month is recommended. 
Based on the studies submitted by the manufacturer to the FDA, upon testing of 1,655 presumed normal samples 16 were confirmed positive resulting in a 1% positivity rate, similar to the prevalence of syphilis in our area. This resulted in a sensitivity of 100% and specificity of 99.8% of our initial, newly introduced screening test.

Specimen Collection:
Collect blood in SST (serum separator tube) 
Centrifuge specimen and send spun SST tube refrigerated to NorDx.  If lab pick up exceeds 48 hours, freeze at -20 degrees C.

Result Reporting: Positive or Negative (can include  the TP-PA reflex result performed at HETL)
References: Expert Consultation Meeting Summary Report, of 2009 in Atlanta, GA
Trep-Sure EIA Antitreponemal EIA screen; Phoenix-Biotech Corp. July 2010

Additional Information:
Contact Monica Ianosi-Irimie, M.D., Ph.D., Laboratory Director, NorDx at (207) 396-7800. Email IANOSM@mmc.org
 

Lyme disease antibody (IgG and IgM), Immunoblot, Serum

Topic: Lyme disease antibody (IgG and IgM), Immunoblot, Serum     Date: 9-30-2015

Test Name Lyme disease IgG and IgM, confirmation Immunoblot  Serum
Test Code LYMIB
Method Immunoblot
Changes Replaces: Lyme Disease Antibody, Immunoblot, Serum LYWB (Mayo Lab)
Specimen 100 uL SST serum 
Test Schedule Monday, Wednesday, Friday, or daily based on volume. Analytical time 1 day 

Change: Effective October 7th, 2015, NorDx will start offering the new confirmation immunoblot for Lyme disease in-house  The Gold Standard Diagnostics Borrelia burgdorferi,  IgM and IgG Line Blot Test Kit is intended for the qualitative detection of IgM and IgG  antibodies to B. burgdorferi in human serum. This test should be performed on samples which have been previously found positive or equivocal using an ELISA or IFA test, to provide supportive evidence of infection with B. burgdorferi.

Methodology: The Gold Standard Diagnostics Borrelia burgdorferi IgM and IgG test is a line blot assay. The antigenic proteins specific for B. burgdorferi B31 (sensu stricto), purified or cloned are transferred individually to a nitrocellulose membrane using a spraying micro-dispensing method. 
During the test procedure, antibodies to B. burgdorferi B31 (sensu stricto) present in the human serum sample will bind to the antigens coated onto the nitrocellulose strips. A secondary antihuman IgM (or IgG) antibody-enzyme conjugate will identify the positive bands. The band pattern will show the presence or absence of specific IgM (or IgG) antibodies to B. burgdorferi infection. 

Interpretation: The analyzed bands, as well as the interpretation of the band patterns is based on guidelines established at the Association of State and Territorial Public Health Laboratory Directors, CDC, the Food and Drug Administration, the National Institutes of Health, the Council of State and Territorial Epidemiologists, and the National Committee for Clinical Laboratory Standards cosponsored the Second National Conference on Serologic Diagnosis of Lyme Disease held October 27-29, 1994.  

Specimen: 100 (minimum 50) μl serum. 
Stability:  8 hours at room temperature, up to 7 days at 2-8°C, and up to 10 freeze and thaw cycles.

Result Reporting: Negative or Positive for IgM (or IgG) antibodies against Borrelia burgdorferi (with enumeration of the positive bands)

References: Package insert: GSD-BBG-120430.D and GSD-BBM-120601.D from 07/14/2014

Additional Information:
Contact Hayley Webber, PhD, Molecular Laboratory Director, (207) 396-7821, webbeh@mmc.org or Monica Ianosi-Irimie, M.D., Ph.D., Laboratory Director, NorDx at (207) 396-7800, ianosm@mmc.org
 

Calprotectin, Feces

Test Name Calprotectin, Feces

Test Code CALFC

Method Enzyme-Linked Immunosorbent Assay (ELISA)

Changes Frozen or refrigerated stool are acceptable. Testing will be performed in-house at NorDx 

Specimen 1-5g stool in a screw-top clean vial. No preservative necessary or indicated.  

Test Schedule Once per week, Saturday or Sunday

 
Introduction:  

Many gastrointestinal disorders present with similar symptoms, therefore, it is important to differentiate Irritable Bowel Disease (IBD) from other diseases.  Radiological and endoscopic techniques are invasive, time-consuming and/or expensive; however, fecal markers offer a non-invasive approach to measuring intestinal inflammation. 

Calprotectin is a calcium and zinc binding protein produced by Polymorphonuclear cells (PMNs), monocytes, and squamous epithelial cells except those in normal skin.  Detection of fecal calprotectin is used to aid in the diagnosis of IBD, specifically Crohn’s disease and ulcerative colitis, and, in conjunction with other clinical and laboratory findings, to differentiate IBD from Irritable Bowel Syndrome (IBS). Organic diseases of the bowel give a strong fecal calprotectin signal with elevations often five to several thousand times the upper reference in healthy individuals, indicating intestinal inflammation.

Fecal calprotectin is an indicator of neutrophilic presence in the stool and is not specific for IBD. Diagnosis of IBD should be based on clinical evaluation, endoscopy, histology, and imaging studies. False-negative results may occur in patients with granulocytopenia due to bone marrow depression. Increased levels of calprotectin may be seen in some patients who are taking Non-steroidal Anti-inflammatory drugs (NSAIDs), and in patients with celiac disease or colorectal cancer. 

Specimen Collection:
Stool Container, urine cup 
1-5 g stool sample
Collection Instructions:
1. Collect a fresh random stool specimen, no preservatives
2. Specimens must be stored at 2-8°C during transport
3. Separate specimens must be submitted when multiple tests are ordered; do not add on to previously collected specimen
4. Specimen cannot be collected from a diaper

Reference Ranges:  
27.1 – 49.9 mg/kg (Normal; No follow-up) 
50.0 – 120.0 mg/kg (Borderline; Re-evaluate at 4 – 6 weeks)

>120.0 mg/kg (Abnormal; Repeat as clinically indicated)                 

References:  
Inova Diagnostics. Quanta Lite Calprotectin Extended Range; package insert version 2. Ref 704860, 2016

Dabritz J, Musci J, Foell D: Diagnostic utility of faecal biomarkers in patients with irritable bowel syndrome. World J Gastroentero 2014;20(2):363-375

Additional Information:  Contact Dr. Monica Ianosi-Irimie, M.D.,Ph.D., Laboratory Director, NorDx, at (207) 396-7800 or ianosm@mmc.org 

 

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