Dear Colleague,In line with our core principles of transparency and building trust with healthcare professionals we report all blood results that we analyze with integrity. We believe it is our duty to our customers to provide them with accurate clinical information and we do this in accordance to the standards required of us by our MS ISO 15189 accreditation. We also want to empower doctors with the knowledge to make better decisions for their patients.

QuantumA Matter of Life

HYPERKALEMIAPATHOGENESIS

Excessive IntakeK+ supplementsHigh K+ diet

Impaired EliminationRenal insufficiencyObstructive uropathyHypoaldosteronismRenal tubular diseaseCongestive heart failureConstipation

Medication:1) ACEI/ARBs2) K+ Sparing Diuretics3) NSAIDs4) Trimethoprim5) Cyclosporin

Intracellular ShiftAcidosisDiabetes MellitusAcute cell-tissue breakdownPeriodic paralysis

Medication:1) Digoxin2) Beta Blockers

Relevant P MHx/ Identifiable acute cause from clinical context

K+>5.5 mmol/L

YES - Treat underlying

cause

NO - Furtherinvestigations

required

Blood Glucose Level - Diabetes MellitusUrinalysis - Renal insufficiencyArterial/Venous Blood Gas - AcidosisSerum CPK - RhabdomyolysisSerum Cortisol and Aldosterone - Adrenal insufficiencySerum Uric Acid and Phosphorus - Tumour lysis syndrome

Consider spurious result if patient asymptomic and above causes unlikely. Refer to spurious results checklist.

Hyperkalemia is a potentially life-threatening medical emergency. If clinically suspected, patient should be urgently treated before further investigations are performed to identify the cause.

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QUANTUM MEDICAL UPDATEIssue 1 www.quantumdxs.comBringing Science to LIFE

Produced by Dr. Tan Shih Yang, Medical Affairssytan@quantumdxs.com

MS ISO 15189

Spurious Hyperkalemia/PseudohyperkalemiaSpurious (false/factitious) hyperkalemia (AKA pseudohyperkalemia) is a common and widely acknowledged problem in the laboratory medicine industry. This is especially so in community-based laboratories working with specimens outside of the hospital environment due to the magnification of the pre-analytical issues highlighted below. Even with our stringent QC processes, a percentage of our samples tested record a potassium reading of >5.5. This finding is consistent across our regional sister labs in Singapore and the Philippines. This document seeks to identify the common causes of spurious hyperkalemia and provide specific measures clinicians can take to help reduce its occurrence.Potassium is an analyte that is very sensitive to pre-analytical conditions. 98% of the body’s potassium is in intracellular stores. This allows the remaining extracellular 2% to be tightly regulated. As a result of this, even a small release of intracellular potassium results in a potentially significant rise in measured potassium values, resulting in a spurious result. For completeness, we have included both the pre-analytical and analytical causes of spurious results. The sections on patient factors and blood collection and storage are the areas that clinicians should pay particular attention to in order to reduce the incidence of spurious hyperkalemia.

Patient Factors Ensure that the patient is calm and not distressed - Hyperventilation associated with fear and crying has been

known to produce a transient hyperkalemic response

Blood Collection and Storage Ensure that best practice venepuncture technique is used - please refer to our supplement on venepuncture best

practice for this

Ensure that the sample is stored correctly after collection – store sample at 15-25°C (specifically, do not store in fridge)

Alternatively, refer the patient to one of Quantum Diagnostics’ collection centres for venepuncture

Logistics

Ensure that the sample is processed within 4 hours of collection - our couriers strive to ensure all our samples reach our lab in the required time window. To enable this, please inform our customer service desk once urgent specimens are ready for collection.

Ensure that the sample is delivered appropriately - our couriers are appropriately trained and provided with the equipment required for transporting samples

Processing and Analysis Ensure that samples are processed appropriately (ie handling, storage and centrifuging) – all of our lab

technicians are trained and abide by our strict standard operating procedures

Ensure that samples are analysed appropriately - our lab operates and abides by strict standard operating procedures and we run the appropriate calibrations and QCs in line with our MS ISO 15189 accreditation

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References:

1. Errors in potassium measurement: a laboratory perspective for the clinician. Asirvatham et al. N Am J Med Sci. 2013 Apr;5(4):255-9.

2. Spurious electrolyte disorders: a diagnostic challenge for clinicians. Liamis et al. Am J Nephrol. 2013;38(1):50-7.

3. Elevated serum potassium levels: the role of preanalytic variables. Stankovic et al. Am J Clin Pathol. 2004 Jun;121 Suppl:S105-12.

Disclaimer of Medical LiabilityQuantum Diagnostics Sdn Bhd and the author are not responsible or liable for any advice, course of treatment, diagnosis or any other information, services or products that an individual obtains through this document. This document is not for use in medical emergencies and users should exercise their own clinical judgment in their practice.