Listen to detailed sample rejection analysis for 2023.
HQE Specimen Rejection Analysis: Chemical Pathology 2023
1. Overall Rejection Rates:
Inpatient specimen rejection rates were consistently higher than those for outpatient and outstation samples across all four quarters:
Jan-Mar: Inpatient 2.29% vs Outpatient/Outstation 1.08%
Apr-Jun: Inpatient 5.4% vs Outpatient/Outstation 2.9%
Jul-Sep: Inpatient 5.7% vs Outpatient/Outstation 2.9%
Oct-Dec: Inpatient 5.1% vs Outpatient/Outstation 2.9%
2. Top Reasons for Specimen Rejection (Overall):
Repeated Test: This was consistently the leading cause of specimen rejection across all quarters.
Test Not Indicated: This consistently ranked as the second or third most common reason for rejection.
No Sample Received: This also consistently featured among the top three reasons for overall rejection, particularly for outpatient samples, major contributor is no sample received for fasting or random blood sugar.
3. Reasons for Inpatient Specimen Rejection:
Repeated Test
Blood Clotted: Particularly for blood gas samples sent in heparinised syringes.
Wrong Container/Fixative
4. Reasons for Outpatient/Outstation Specimen Rejection:
Repeated Test
No Sample Received: Especially for fasting or random blood sugar tests where plasma was not sent in sodium fluoride tubes as required.
Haemolysed Sample: Often in plain/gel tubes. The January-March report indicates this as a significant contributor.
5. Issues with Request Forms and Specimen Labelling:
Across all reports, a significant number of rejections were due to incomplete or incorrect request forms, including missing patient names/identification numbers, location details, test names, requestor information, and clinical summaries.
Incomplete labelling of specimens (missing name, IC number, test name) and discrepancies between information on the form and label were also persistent issues.
6. Unsuitable Specimens:
Beyond haemolysed and clotted samples, other reasons for specimen rejection included:
Wrong container/fixative
Improper specimen volume (underfilled/overfilled)
Specimen leaking
Decomposed/degenerated specimens
Wrong specimen/wrong sampling time
Tube/container expired
7. Blood Gas Sampling Errors:
All reports identified clotted blood gas samples as a major contributor to inpatient specimen rejection. The corrective actions section in each report provides detailed instructions on proper blood gas sampling procedures to mitigate this, including:
Proper heparinisation of the syringe ("Heparin should be taken in the syringe to lubricate the inner wall of the syringe and then heparin should be expelled from the syringe completely.").
Immediate and thorough mixing of the sample post-sampling.
Immediate transportation of the sample to the laboratory in an ice-water slurry.
Emphasis on stating arterial or venous sampling and time on the form, proper patient identification, and labelling the syringe before collection.
8. Top Contributing Locations:
January to March: Yellow Zone, Nephrology Clinic, and Acute Internal Medical Ward (AIMW).
April to June: Yellow Zone, General Medical Ward 4 (GM4), and Nephrology clinic.
July to September: Yellow Zone, General Medical Ward 1 (GM1), and Nephrology clinic.
October to December: Yellow Zone, Nephrology clinic, and General Medical Ward 3 (GMW3).
9. Corrective Actions:
Addressing Repeated Test Requests: Clearly defining and communicating the testing intervals for various chemical pathology tests (e.g., Liver Function Test once in 3 days, Thyroid Function Test once every 2 weeks) and advising consultation with medical officers/pathologists for requests outside these intervals.
Preventing "Test Not Indicated" Rejections: Emphasising the screening of special (non-routine) biochemistry test requests based on clinical history and diagnosis, requiring complete and relevant clinical information on the request form.
Improving Sample Collection for Glucose: Specifically highlighting the need for Fluoride Oxalate tubes (grey cap) for blood sugar requests and the correct handling of outstation samples (plasma separation).
Reducing Clotted Blood Gas Samples: Providing detailed guidelines on proper heparinisation, mixing, and immediate transport of blood gas samples.
Minimising Haemolysed Samples: Offering guidance on correct venipuncture techniques, including appropriate needle gauge, allowing alcohol to dry, limiting tourniquet time, avoiding forceful plunger retraction, and gentle handling of tubes. The January-March report adds, "Difficult venipuncture and improper handling of collected specimens increases the risk of specimen hemolysis and rejection."
Referring to the Laboratory Handbook: Directing staff to the HQE Laboratory Handbook for detailed information on testing intervals and sample tube requirements.
Conclusion:
The analysis of specimen rejection data for 2023 highlights several recurring issues within the Chemical Pathology Unit at HQE. While the overall rejection rates for outpatients remained relatively stable, the higher and fluctuating rates for inpatients require focused attention. The consistent prominence of "repeated test," "test not indicated," and preanalytical errors (particularly with blood gas and sample suitability) indicates areas where targeted interventions and improved adherence to guidelines are crucial. The identification of specific high-contributing locations allows for focused educational and procedural improvements within those areas. The corrective actions outlined in the reports provide a framework for addressing these issues and working towards a reduction in unnecessary specimen rejections. Continuous monitoring and feedback mechanisms will be essential to assess the effectiveness of these actions and ensure sustained improvement in specimen quality.