Rejection Criteria

There are four basic factors that serve as a foundation for rejecting or accepting specimens:

1. Specimen labeling problems (e.g. missing or incorrect information)
2. Requisitioning difficulties
3. Specimen integrity problems (e.g. being sent a wrong tube or inadequate volume)
4. Result integrity problems (e.g. pre-analytical conditions such as hemolysis or unexplained delta      check failure)

If a sample is rejected or if testing is continued, the first priority is always the effect on patient care. It is extremely important to prevent the inappropriate acceptance of a specimen whose test results could harm a patient due to misdiagnosis or incorrect treatment. The following are some of the problems that can occur and may call for rejection:

Blood collection problems

  • Clotted sample for whole blood or plasma tests
  • Gross hemolysis
  • IV fluid contamination
  • Insufficient quantity
  • Incorrect collection tube or container
  • Serum or plasma not separated from cells
  • Plasma not frozen when needed

Urine collection problems

  • Urine contaminated with stool
  • Specimen collection time not confirmed
  • Delivery delay

Culture collection problems

  • Specimen received damaged or leaking
  • Grossly contaminated specimen.
  • Unrefrigerated urine culture
  • Refrigerated GC or blood culture
  • MRSA screen not collected on proper swab

Sputum Gram Stain

Sputum specimens are to be rejected as unsatisfactory when gram stain results do not meet specific criteria. Nurses are notified and result documented in the LIS. Specimens that are rejected will be held if physician requests culture to be worked up on the specimen.

Stool Specimens

Stool specimens for Culture or Ova & Parasite on inpatients should not be submitted after the 3rd hospital day without consultation. Stools should be tested for clostridium difficile for patients over the age of 2 years with clinically significant diarrhea and history of antibiotic exposure as an alternative to routine culture. Only Liquid, unformed stool will be tested by microbiology. Formed stool samples will be discarded. Only one (1) stool sample for C. difficile will be tested by microbiology during a 7 day period. Additional samples will be discarded.


  • No order slip received with specimen
  • Unsigned Blood Bank slip
  • Wrong orders with a specimen
  • No diagnosis code