Prenatal – Serology
Conformément au Règlement de l’Ontario 671/92 de la Loi sur les services en français, les renseignements d’analyses de laboratoire liés à la présente page ne sont offerts qu’en anglais parce qu’ils sont de nature scientifique ou technique et destinés uniquement à l’usage des fournisseurs de soins de santé qualifiés et non aux membres du public.
Background
This page provides prenatal serology testing information for HIV, Syphilis, Rubella and Hepatitis B surface antigen at Public Health Ontario (PHO). For information regarding each testing option, refer to the following PHO webpages:
- Updated acceptance/rejection criteria to indicate that donor testing is not available through PHO.
- Minor updates to the submission and collection notes to improve clarity.
- Updated instructions for STAT requests.
- Updated reporting to indicate that cumulative reporting is no longer available.
Testing Indications
All pregnant women should be screened for HIV, syphilis, rubella and hepatitis B surface antigen (HBsAg). HBsAg tests for active HBV infection. Testing for hepatitis B immunity (HBsAb) is not required for prenatal screening and will be rejected unless a clear reason for testing (e.g. exposure to a case, needlestick injury, etc.) is indicated on the requisition.
In Ontario, it is recommended that all pregnant individuals be offered HIV testing regardless of their apparent risk. Testing is recommended with each pregnancy since they may have become infected in the interim.
Syphilis screening is recommended for pregnant people in their first trimester or at the first prenatal visit. Repeat screening in pregnancy should be considered for individuals with ongoing or high risk.
Acceptance/Rejection Criteria
- Donor testing is not available through PHO. Specimens from patients being screened as potential donors (e.g. organ, tissue, cells, fertility, etc.) should be referred to a laboratory that performs donor screening assays. Specimens submitted for donor screening to PHO will be rejected.
- Testing for hepatitis B immunity (HBsAb) is not required for prenatal screening and will be rejected unless a clear reason for testing (e.g. exposure to a case, needlestick injury, etc.) is indicated on the requisition.
- Routine testing for hepatitis A during prenatal screening is not currently recommended and will not be performed unless clinically indicated (e.g. outbreak investigation, etc.)
- Specimens with mismatched information on the label and requisition will be rejected.
- Haemolysed, icteric, lipemic or microbially contaminated sera is not recommended for testing.
Specimen Requirements
| Test Requested | Required Requisition(s) | Specimen Type | Minimum Volume | Collection Kit |
HIV |
Serum |
2 mL serum |
Serum Separator Tube (SST) |
Submission and Collection Notes
Complete all fields of Prenatal Screening Requisition. Indicate the prenatal screen test requested by checking the box(es) in Section 3 – Test(s) Requested.
Label the specimen tubes(s) with the patient’s first and last name, date of collection, and one other unique identifier such as the patient’s health card number or date of birth. For additional information see: Criteria for Acceptance of Patient Specimens. Failure to provide this information may result in rejection or testing delay. Patient information on the specimen must match the requisition.
PHO prefers centrifuged serum separator tubes for serological testing requests.
Generally, only one full draw 5 mL SST is needed for testing a combination of up to six infectious disease serology markers. If a full tube cannot be drawn, submit two tubes. Refer to Serology Testing – Laboratory Specimen Collection and Submission Instructions for more information.
Do not submit glass tubes.
Storage and Transport
Place specimen tube in biohazard bag and seal it. Place completed Prenatal Screening Requisition in the pouch at the front of the biohazard bag.
To avoid delays in testing, ship specimens for testing to PHO immediately after collection or processing. Store specimen tubes at 2-8°C following collection and centrifugation, and ship to PHO’s laboratory on ice packs. If delayed shipping is anticipated, remove serum from clot and store frozen at -20°C or colder, and ship on dry ice.
All clinical specimens must be shipped in accordance with the Transportation of Dangerous Good Act
Test Frequency and Turnaround Time (TAT)
Rubella - Serology testing is performed daily Monday to Friday. Turnaround time is up to three days from receipt by PHO.
Syphilis, HIV, and HBsAg – Serology screen testing is performed daily Monday to Friday.
Turnaround time is up to 3 days from receipt by PHO for non-reactive samples and up to six days for reactive samples.
Refer to the following PHO webpages for detailed information:
STAT and Critical Specimens Testing
STAT testing is only available for HBsAg and/or HIV serology for individuals in labor with no prenatal testing and at high risk for HBV and/or HIV infection.
Prior to sending, PHO’s Customer Service Centre must be notified at 416-235-6556/1-877-604-4567. Contact the After-Hours Emergency Duty Officer at 416-605-3113 if outside of PHO’s laboratory operating hours.
“STAT” specimens must be shipped separately from routine specimens. The outer packaging must clear be marked “STAT” and handled in accordance with the Canadian Biosafety Standards. Specimens must be shipped in accordance with the Transportation of Dangerous Goods Regulations.Failure to ship separately, specimen will be tested as routine.
Prenatal screening serology is performed using a chemiluminescent microparticle immunoassay (CMIA) for the qualitative detection of the respective markers in human serum.
Algorithm
RUBELLA: refer to the Rubella – Serology Test Information Sheet
SYPHILIS: refer to the Syphilis – Serology Test Information Sheet
HIV: refer to the HIV – Diagnostic Serology Test Information Sheet
HEPATITS B SURFACE ANTIGEN (HBsAg): if HBsAg is reactive, further testing for anti-HBV core total antibody (anti-HBc Total) and/or HBsAg confirmatory testing is performed.
Interpretation
Results are reported as reactive or non-reactive. Please refer to the Test Information Sheets above for specific interpretations.
Reporting
Results are reported to the physician, authorized health care provider (General O. Reg 45/22, s.18) or submitter as indicated on the requisition.
Specimens that are positive for syphilis, HIV, and/or HBsAg are reported to the Medical Officer of Health as per the Ontario Health Protection and Promotion Act.
Due to changes in PHO’s and Ontario’s laboratory information systems, cumulative reporting is no longer available.
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