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Critical Values

Diagnostic Services: AB - NWT

Diagnostic Services AB/NWT considers certain test results to be “critical values”. Critical result values will be reviewed by the Canadian Blood Services Medical Director / designate and verbally communicated to the requesting facility laboratory, responsible nurse and/or responsible physician as appropriate.

AB-NWT Test Interpretation - Critical Values (PDF)


Test Interpretation - Critical Values

Crossmatch Testing

  • Unmatched units have been issued and patient was found to have a positive antibody screen upon completion of testing.
  • Unmatched units have been issued and are later found to be incompatible upon completion of testing.
  • Significant antibody(ies) has/have been identified and we are unable to provide crossmatch compatible units.
  • Significant antibody(ies) has/have been identified and it may be difficult to obtain compatible units in the future.
  • A hemolytic transfusion reaction is suspected.

Perinatal Testing

  • Positive DAT on cord sample requiring that the baby be monitored for signs of jaundice.
  • Kleihauer Betke results requiring that greater than 15mL dose of RhIG be administered.
  • Anti-K is detected in maternal sample.
  • Clinically significant antibody with a titre ≥ 16 in maternal sample.