2024 analysis

Review of Haematology Sample Rejection Analysis at Hospital Queen Elizabeth (2024)

1. Overall Rejection Rates and Contribution by Unit:

Across all four quarters of 2024, the overall rejection rate for inpatient specimens at Hospital Queen Elizabeth consistently exceeded the 1% threshold. The Haematology Unit was a significant contributor to this higher-than-desired rejection rate in each period:

1.     Jan-Mar 2024: Overall rate 2.19%, Haematology Unit 2.90%

2.     Apr-Jun 2024: Overall rate 2.30%, Haematology Unit 3.47%

3.     Jul-Sep 2024: Overall rate 2.53%, Haematology Unit 3.49%

4.     Oct-Dec 2024: Overall rate 2.28%, Haematology Unit 3.11%

Key Finding: The Haematology Unit consistently exhibits a rejection rate significantly higher than the 1% target and often higher than other pathology units (Chemical Pathology and Microbiology).

2. Primary Reasons for Haematology Specimen Rejection:

The dominant reason for haematology specimen rejection across all four reporting periods was the specimen being unsuitable for testing. Specifically, within the Haematology Unit, the most frequent reasons for rejection were consistently:

1. Blood Clotted Samples: This was the leading cause of rejection in every quarter. The number of rejected samples due to clotting ranged from 893 (Apr-Jun) to 996 (Jul-Sep).

2. Improper Specimen Volume (Underfilled/Overfilled): This consistently ranked as the second highest reason for rejection, with numbers ranging from 418 (Jan-Mar) to 834 (Jul-Sep).

3. Test Not Indicated: This was another significant reason for rejection, particularly for outpatient and outstation samples.

4. No Sample Received: A notable number of cases were rejected because no sample was received.

5. Repeated Test: While not always in the top three, repeated tests were a consistently high rejection reason, particularly in the later quarters.

6. Other contributing factors included Hemolysis, Incomplete Labeling, Decomposed/Degenerated Specimens, and Wrong Container/Fixative.   

Key Finding: Issues related to specimen integrity (clotting, incorrect volume) are the primary drivers of haematology sample rejections. Inadequate clinical information on the request form and samples not arriving at the lab also contribute significantly.

3. Frequently Rejected Haematology Tests:

Across all four quarters, the following tests were consistently among those most frequently rejected:

1. Full Blood Count (FBC)

2. Prothrombin Time / Activated Partial Thromboplastin Time (PT/APTT)

3. Erythrocyte Sedimentation Rate (ESR)

4. Haemoglobin Analysis (Hb Analysis)

5. Peripheral Blood Film (PBF)

Key Finding: These high-volume and critical tests are frequently impacted by the identified rejection reasons, potentially delaying diagnosis and treatment.

4. Wards with the Highest Contribution to Haematology Sample Rejections:

The wards contributing the most to haematology sample rejections varied slightly across the four quarters, but some units appeared consistently:

1. AIM (Acute Internal Medicine)

2. ICU 2 (Intensive Care Unit 2)

3. GM2 (General Medicine 2)

4. GM3 (General Medicine 3)

5. GM4/AIM (General Medicine 4 / Acute Internal Medicine)

Key Finding: Certain inpatient units consistently contribute a higher proportion of rejected haematology samples, suggesting potential areas for targeted intervention and training. AIM and ICU 2 appear as recurring high contributors.

5. Proposed Improvement Measures (Consistent Across Reports):

All four reports included similar recommendations for improvement, focusing on addressing the primary causes of rejection:

1. Preventing Blood Clotting:

   1. Improved blood collection techniques.

   2. Proper mixing of blood with additives/anticoagulants in specimen tubes (8-10 inversions for EDTA, 3-4 for sodium citrate).

   3. Avoiding delays in sample transportation to the laboratory.

2. Ensuring Adequate Specimen Volume:

   1. Adherence to volume markings on specimen tubes, particularly crucial for coagulation (e.g., sodium citrate tubes).

3. Specific Guidance for ESR Samples:

   1. Analysis within 4 hours of collection.

   2. Performance during office hours (as offered by the Haematology lab in Complex D).

   3. Avoiding collection outside office hours.

   4. Not sharing request forms with other tests (e.g., FBC or PT/APTT).

4. Appropriate Use of Hb Analysis: Highlighting that Hb Analysis is a screening test for thalassaemia and not an initial screening for anaemia. Emphasising that low Hb levels can affect results, and iron deficiency anaemia should be treated before requesting Hb Analysis.

5. Complete Clinical Details for PBF and Referral Tests: Ensuring sufficient clinical information is provided for Peripheral Blood Film (PBF) and tests sent to reference laboratories.

6. Minimising Haemolysis:

   1. Improved blood collection techniques.

   2. Using appropriate needle sizes (smaller needles can cause trauma).

   3. Ensuring alcohol swabs are dry before blood collection.

   4. Gentle and proper mixing of samples.

   5. Avoiding delays in sample transportation.

7. Guidance on Repeat FBC Tests: FBC tests should not be repeated on the same day without consulting the Pathology Department's Medical Officers.

8. Pre-Transportation Checks: Wards should ensure samples are ready for dispatch to avoid "no sample received" rejections (mentioned specifically in the Jan-Mar report).

Key Finding: The repeated inclusion of these specific recommendations across all reports underscores the consistent nature of the problems and the proposed solutions. Addressing these areas should lead to a reduction in haematology specimen rejection rates.

Conclusion:

The analysis consistently reveals that high rejection rates in the Hematology Unit at Queen Elizabeth Hospital are primarily driven by issues related to sample collection, handling, and transportation. The most frequent causes are blood clotting, improper volume, and tests being ordered when not indicated or as repeats without proper consultation. Specific wards, including AIM and ICU 2, are consistently identified as major contributors to these rejections. The reports provide clear and consistent recommendations focusing on improving pre-analytical procedures to address these recurring issues.