2025 analysis

Analysis of Hematology Specimen Rejection at Hospital Queen Elizabeth (2025)

Hematology specimen rejection rates at Hospital Queen Elizabeth throughout the 2025 calendar year reveals a consistent failure to meet the institutional target of a rejection rate below 1%. 

Statistical Overview of Specimen Rejections

Quarterly Performance Trends (Inpatient)

Jan - Mar 3.08%

Apr - Jun 2.98%

Jul - Sep 3.18%

Oct - Dec 3.43%

Primary Causes of Rejection

1. Blood Clotted: The most significant issue, consistently accounting for approximately 1,000 rejected samples per quarter.

  * Jan-Mar: 1,027 samples

  * Apr-Jun: 988 samples

  * Jul-Sep: 1,006 samples

  * Oct-Dec: 1,068 samples

2. Improper Specimen Volume: Specimens that are underfilled or overfilled fail to maintain the required blood-to-additive ratio. This category saw a significant increase in the latter half of the year, rising from 371 cases in Q1 to 494 cases in Q4.

3. No Sample Received: A persistent administrative/logistical failure where request forms arrive without the corresponding specimen, averaging over 200 cases per quarter.

4. Clinical/Technical Discrepancies: This includes "Test Not Indicated" (peaking at 232 cases in Q2), "Decomposed/Degenerated specimens," and missing clinical summaries.

The following tests are most susceptible to rejection due to strict volume and integrity requirements:

* FBC (Full Blood Count): Impacted heavily by clotted samples and minimum volume requirements (1ml).

* PT/APTT (Coagulation): Highly sensitive to improper volume and clotting.

* Hb Analysis: Frequently rejected due to clinical prerequisites not being met (e.g., normal MCV/MCH or untreated iron deficiency).

* PBF (Peripheral Blood Film): Often rejected due to missing required clinical details.

Source Contribution: Wards 

1. HDW (High Dependency Ward)-Clotted samples, improper volume

2. GM2 / GM1 / GM4 (General Medicine)-Clotted samples, improper volume, repeated tests

3. ICU 1 / ICU 2-Improper volume, no sample

4. GSW 1 / GSW 3-Clotted samples, clinical detail omission

5. GASW-Rejection volume increased in Q4

Focused Analysis: Thalassemia Screening (Hb Analysis)

Hb Analysis rejections are often driven by clinical parameters rather than just technical errors. Leading causes include:

1. Normal MCV and MCH: Specimens are rejected if these indices do not indicate a need for thalassemia screening.

2. Iron Deficiency Anemia: This must be treated before an Hb Analysis is requested, as low iron levels can influence the results.

3. Clotted Samples and Improper Labeling: Significant technical contributors to rejection.

4. Redundancy: Requests for tests that have recently been completed or are unnecessary given the patient's history.

Recommendations for Improvement

To reduce rejection rates below the 1% threshold, the following protocols must be strictly enforced:

1. Prevention of Clotted Samples and Hemolysis

1. Mixing Technique: Specimens must be mixed immediately after collection using the inversion method.

   1. EDTA Tubes: 8–10 inversions.

   2. Sodium Citrate Tubes: 3–4 inversions.

Note: One inversion consists of a full 180-degree turn and back. Samples must not be shaken roughly.

2. Needle Selection: Use appropriate needle sizes; small needles cause trauma to blood cells, leading to hemolysis.

3. Alcohol Prep: Ensure alcohol swabs have dried completely before skin puncture.

2. Specimen Volume and Timing

1. 1. Volume Accuracy: Ensure blood is drawn exactly to the fill line marked on the tube, particularly for coagulation tests.

   2. FBC Requirements: A minimum volume of 1ml is mandatory.

   3. ESR Constraints: ESR samples must be analyzed within 4 hours. These tests should only be taken during office hours as they are handled by the Hematology Laboratory in Complex D.

3. Clinical and Administrative Compliance

1. 1. Thalassemia Screening: Do not request Hb Analysis as an initial screening for anemia. Treat iron deficiency first and ensure recent FBC results are available.

   2. Clinical Details: PBF and tests sent to reference labs must include comprehensive clinical summaries.

   3. Duplicate Testing: FBC tests cannot be repeated on the same day. For exceptions, clinicians must contact the Pathology Department medical officers at extensions 4247, 7329, or 8241.

   4. Logistics: Avoid delays in transporting samples to the laboratory to prevent specimen decomposition.

Conclusion

The Unit Hematology consistently reported the highest rejection rates, peaking at 3.43% in the final quarter. The primary technical cause for rejection across all periods was clotted blood samples, followed by improper specimen volume (underfilled or overfilled). Specific tests, including Full Blood Count (FBC) and Coagulation profiles (PT/APTT), were the most frequently impacted. High Dependency Wards (HDW) and General Medicine wards (GM1, GM2, GM4) were identified as the leading contributors to these figures. Remediation efforts must focus on improving phlebotomy techniques, ensuring proper specimen inversion, and adhering to specific test requirements for thalassemia screening.