Pseudohyperkalaemia is a common finding in myeloproliferative disorders that may lead to inappropriate management of patients

Stability of potassium, calcium and phosphorus electrolytes in three different tubes in patients with essential thrombocytosis

Proper blood collection and timely analysis are vital steps for reliable results. This study aims to compare potassium(K), calcium(Ca), and phosphorus(P) concentrations in serum separator tube (SST), lithium heparin tube without gel (LiH), and lithium heparin tube with a barrier (Barricor)tubes in essential thrombocytosis(ET) patients. Additionally, we assessed short-term stability of these analytes at room temperature. K, Ca and P concentrations of blood taken from 40 ET patients into SST, LiH and Barricor tubes were measured at 0, 2, 4 and 8 h. We calculated the percentage difference and defined the maximum permissible difference (MPD) using the Biological Variation Database. Intertube comparisons were conducted using Passing-Bablok regression and Bland-Altman analysis. Comparing SST to LiH, the percentage difference values for all tests exceeded the MPD. When comparing Barricor to LiH, K and Ca tests were above MPD, except for P. At the 8th hour, LiH showed clinically significant changes in all three electrolytes. Barricor exhibited stability for K, Ca, and P for up to 8 h, with only Ca levels borderline higher than the MPD. Our study reveals clinically significant alterations in K, Ca, and P concentrations in SST compared to LiH tubes, and in K and Ca concentrations in Barricor compared to LiH tubes. While K, Ca and P concentrations were stable for up to 4 h at room temperature in all tube types tested, significant changes were observed in all electrolytes at 8 h in the LiH tube.

Erroneous potassium results: preanalytical causes, detection, and corrective actions

Potassium is one of the most requested laboratory tests. Its level is carefully monitored and maintained in a narrow physiological range. Even slightly altered potassium values may severely impact the patient's health, which is why an accurate and reliable result is of such importance. Even if high-quality analytics are available, there are still numerous ways in which potassium measurements may be biased, all of which occur in the preanalytical phase of the total laboratory testing process. As these results do not reflect the patient's in-vivo status, such results are referred to as pseudo-hyper/hypokalemia or indeed pseudo-normokalemia, depending on the true potassium result. Our goal in this review is to present an in-depth analysis of preanalytical errors that may result in inaccurate potassium results. After reviewing existing evidence on this topic, we classified preanalytical errors impacting potassium results into 4 categories: 1) patient factors like high platelet, leukocytes, or erythrocyte counts; 2) the sample type 3) the blood collection procedure, including inappropriate equipment, patient preparation, sample contamination and others and 4) the tube processing. The latter two include sample transport and storage conditions of whole blood, plasma, or serum as well as sample separation and subsequent preanalytical processes. In particular, we discuss the contribution of hemolysis, as one of the most frequent preanalytical errors, to pseudo-hyperkalemia. We provide a practical flow chart and a tabular overview of all the discussed preanalytical errors including possible underlying mechanisms, indicators for detection, suggestions for corrective actions, and references to the according evidence. We thereby hope that this manuscript will serve as a resource in the prevention and investigation of potentially biased potassium results.

Spurious Electrolyte and Acid-Base Disorders in the Patient With Cancer: A Review

Electrolyte and acid-base disorders are frequently encountered in patients with malignancy, either due to cancer itself or as a complication of its therapy. However, spurious electrolyte disorders can complicate the interpretation and management of these patients. Several electrolytes can be artifactually increased or decreased such that the serum electrolyte values do not correspond to their actual systemic levels, potentially resulting in extensive diagnostic investigations and therapeutic interventions. Examples of spurious derangements include pseudohyponatremia, pseudohypokalemia, pseudohyperkalemia, pseudohypophosphatemia, pseudohyperphosphatemia, and artifactual acid-base abnormalities. Correctly interpreting these artifactual laboratory abnormalities is imperative for avoiding unnecessary and potentially harmful interventions in cancer patients. The factors influencing these spurious results also must be recognized, along with the steps to minimize them. We present a narrative review of commonly reported pseudo electrolyte disorders and describe strategies to exclude erroneous interpretations of these laboratory values and avoid pitfalls. Awareness and recognition of spurious electrolyte and acid-base disorders can prevent unnecessary and harmful treatments.

Markedly increased small-sized megakaryocytes and platelets count in the circulation with pseudo-hyperkalemia following splenectomy

Megakaryocytes are common in the bone marrow and appear less often in circulation. Most studies on circulatory megakaryocytes have implicated myelodysplastic syndromes and myeloproliferative disorders because of disruption of the bone marrow barrier and extramedullary hematopoiesis that is commonly seen in the spleen. As myeloproliferative disorders progress, particularly in the absence of the spleen, it is very likely that considerable numbers of megakaryocytes are present in the circulation. Myeloproliferation is associated with essential thrombocytosis or leukocytosis and is the leading cause of pseudo-hyperkalemia followed by reactive thrombocytosis due to splenectomy, rheumatoid arthritis, and renal cancer. The simultaneous measurement of plasma potassium is required when the platelet count exceeds 500 × 10⁹/L and the level of serum potassium is  > 5.4 mmol/L.

Pseudohyperkalemia and the Need for Imperative Caution With the Newly Introduced Potent Potassium Binders: Two Cases

Pseudohyperkalemia was first reported in 1955 by Hartmann and Mellinkoff, as a marked elevation of serum potassium in the absence of clinical evidence of electrolyte imbalance - simultaneous serum potassium exceeds plasma potassium by >0.4 mmol/L. We describe two patients with pseudohyperkalemia who inadvertently received inappropriate potassium binder therapy for weeks to months before the diagnosis of pseudohyperkalemia was entertained and subsequently confirmed. Potassium binders ultimately were promptly discontinued once the diagnosis of pseudohyperkalemia was confirmed. Physicians’ attention must be drawn to the availability of the new potent oral potassium binders, patiromer and sodium zirconium cyclosilicate. We strongly advocate for imperative caution with these new binders. Iatrogenic life-threatening hypokalemia remains a real concern and must be avoided. Our patients highlighted the importance of caution in the use of the newer potent potassium binders to mitigate against the causation of iatrogenic hypokalemia. Also as important is the observation that in the same patient, with changing clinical scenarios, a patient might exhibit true hyperkalemia that alternated with pseudohyperkalemia, the first of such a report.

Acute Myocardial Infarction Followed by Cerebral Hemorrhagic Infarction in Polycythemia Vera: Case Report and Literature Review

A 60-year-old man presented to our emergency room with severe chest pain. Based on the electrocardiogram and elevated serum troponin T levels, acute coronary syndrome was suspected. Coronary angiography revealed total occlusion of the middle of the left anterior descending coronary artery. However, blood cell count abnormalities were not of concern. Twelve days later, the patient developed hemorrhagic infarction in the right parieto-occipital lobe. Acute coronary syndrome and cerebral hemorrhagic infarction were primarily caused by thrombus formation due to polycythemia vera (PV), based on the presence of increased blood consistency on admission. PV was diagnosed after bone marrow biopsy and genetic testing. The patient was treated with descending cell and antiplatelet therapy. Our case highlights the importance of the urgent identification of PV. When acute myocardial infarction occurs in patients with no significant risk factors for cardiovascular disease, blood routine abnormalities should be paid close attention to. If PV was diagnosed as early as possible, thrombotic and hemorrhagic complications could be prevented in the early stages.

Pseudohyperkalemia caused by essential thrombocythemia in a patient with chronic renal failure: A case report

BACKGROUND

Hyperkalemia is one of the most common complications of chronic renal failure. Pseudohyperkalemia is caused by elevated levels of serum potassium in vitro and is usually accompanied by thrombocythemia. Although an elevated level of potassium is typically correlated with impaired renal function, pseudo-hyperkalemia has been rarely reported in patients with chronic renal failure. Here, we conducted a review of the literature to study the case of pseudo-hyperkalemia caused by the essential thrombocythemia in a patient with chronic renal failure.

CASE SUMMARY

A 73-year-old woman was admitted to our hospital with complaints of palpitation, dyspnea, and acratia for 2 d and a history of essential throm-bocythemia for 1 year. The routine blood test showed platelet count of 1460 × 10⁹/L, and biochemistry tests showed that the patient suffered from hyperkalemia (potassium: 7.50 mmol/L) and renal failure (estimated glomerular filtration rate: 8.88 mL/min). Initial treatment included medicines to lower her potassium-levels and hemodialysis. However, the therapy did not affect her serum potassium levels. Plasma potassium concentration measurements and a history of essential thrombocythemia established the diagnosis of pseudohyperkalemia. The treatments of the platelet disorder gradually normalized serum potassium levels; however, the treatments had to be discontinued later due to the severe leukopenia, and enhanced levels of serum potassium concentrations were observable in the patient. Since plasma sampling was not permitted, doctors had to use a diuretic just in case. Finally, the patient collapsed into unconsciousness and died due to multiple organ dysfunction and electrolyte disturbance.

CONCLUSION

We reviewed the literature and suggest that serum and plasma potassium values should both be measured for patients whose platelet counts exceed 500 × 10⁹/L to eliminate chances of pseudohyperkalemia, especially for those with chronic renal failure. An inappropriate treatment for pseudohyperkalemia can aggravate a patient's condition.

Potassium regulation in the neonate

Potassium, the major cation in intracelluar fluids, is essential for vital biological functions. Neonates maintain a net positive potassium balance, which is fundamental to ensure somatic growth but places these infants, especially those born prematurely, at risk for life-threatening disturbances in potassium concentration [K⁺] in the extracellular fluid compartment. Potassium conservation is achieved by maximizing gastrointestinal absorption and minimizing renal losses. A markedly low glomerular filtration rate, plus adaptations in tubular transport along the nephron, result in low potassium excretion in the urine of neonates. Careful evaluation of clinical data using reference values that are normal for the neonate's postmenstrual age is critical to avoid over-treating infants with laboratory results that represent physiologic values for their developmental stage. The treatment should be aimed at correcting the primary cause when possible. Alterations in the levels or sensitivity to aldosterone are common in neonates. In symptomatic patients, the disturbances in [K⁺] should be corrected promptly, with close electrocardiographic monitoring. Plasma [K⁺] should be monitored during the first 72 h of life in all premature infants born before 30 weeks of postmenstrual age as these infants are prone to develop non-oliguric hyperkalemia with potential serious complications.

Pseudohyperkalaemia: a rare complication of splenectomy

Pseudohyperkalaemia is an uncommon and frequently unrecognised biochemical abnormality. It occurs as a consequence of aggregation and lysis of platelets in vitro. As a result, potassium is released, which causes an elevated serum concentration. We present the case of a 21-year-old man with a traumatic splenic injury necessitating laparotomy and splenectomy. Following surgery he developed hyperkalaemia. Further investigations diagnosed pseudohyperkalaemia, one of the causes of which is thrombocytosis secondary to splenectomy.

Spurious electrolyte disorders: a diagnostic challenge for clinicians

Spurious electrolyte disorders refer to an artifactually elevated or decreased serum electrolyte values that do not correspond to their actual systemic levels. When a clinician is confronted with a case of electrolyte disturbance, the first question should be whether it is an artifact. Spurious electrolyte disorders (pseudohyponatremia, pseudohypernatremia, pseudohypokalemia, pseudohyperkalemia, pseudohypomagnesemia, pseudohypophosphatemia, pseudohyperphosphatemia, pseudohypocalcemia and pseudohypercalcemia) are not infrequently observed in clinical practice. The recognition that an electrolyte disturbance may be an artifact may prevent inappropriate therapeutic interventions that could potentially have unfavorable outcomes. Clinicians must be alert to the possibility of spurious laboratory abnormalities when faced with conflicting laboratory values or measurements that are discordant with the clinical presentation. Moreover, in the presence of conditions that predispose to spurious electrolyte disorders, the normal measured electrolyte levels should raise the suspicion that true electrolyte disorders may be present.

Unexplained hyperkalemia: The tip of the iceberg

BACKGROUND

Hyperkalemia is a potentially life-threatening medical condition; on the other hand pseudohyperkalemia is a benign entity, which should be suspected when serum potassium is elevated without concomitant electrolyte imbalances or remarkable degree of renal dysfunction. Patients seldom have the classical manifestations of hyperkalemia. Failure to recognize this condition causes anxiety among physicians, unnecessary laboratory testing and unwarranted treatments.

CASE REPORT

We describe a sixty-year-old woman with persistent hyperkalemia and mean platelet count over a six-month period of 1015×10(3) cells/cumm. Based on this finding of thrombocytosis an immediate hematological evaluation has detected a myeloproliferative disorder, specifically essential thrombocythemia. Normalizing platelet count was paralleled by resolution of hyperkalemia.

CONCLUSIONS

Pseudohyperkalemia might be the tip of the iceberg to a major underlying pathological process. Unless a high index of suspicion to diagnose this disorder is maintained it will continue to be remarkably under diagnosed, subjecting patients to numerous unnecessary tests and treatments.

Pseudohyperkalemia in a patient with chronic lymphoblastic leukemia and tumor lysis syndrome

Purpose:

Recognition of pseudohyperkalemia is essential to prevent medical mismanagement of erroneous hyperkalemia. The purpose of this case is to describe pseudohyperkalemia attributed to malignant leucocytosis in a patient with chronic lymphoblastic leukemia and tumor lysis syndrome. Methods for determination of pseudohyperkalemia are discussed.

Summary:

A 75-year-old male with progressive chronic lymphoblastic leukemia was hospitalized for medical evaluation and chemotherapy administration. Notable laboratory findings included white blood cell count of 479 × 103 cells/µL (4.00 × 103 cells/µL–10.80 × 103 cells/µL) with 95% lymphocytes (20%–50%) and 5% blasts (zero) present in the differential, serum potassium 9.8 mM/L (3.4 mM/L–5.0 mM/L), uric acid of 11.8 mg/dL (3.5 mg/dL–8.0 mg/dL), serum creatinine 1.47 mg/dL (0.60 mg/dL–1.30 mg/dL), and lactate dehydrogenase of 2529 IU/L (100 IU/L–220 IU/L). The patient was anemic (Hb 7.6 g/dL (14.0 g/dL–18.0 g/dL)) and thrombocytopenic (17 × 103 platelets/μL (140 × 103 platelets/μL–400 × 103 platelets/μL)). There were no electrocardiographic findings indicating systemic hyperkalemia. Repeat analysis of the blood potassium level using a heparinized tube assayed immediately after specimen collection demonstrated a plasma potassium level 4.1 mM/L. Subsequent analysis of specimens using similar methodology demonstrated potassium results within the normal limits despite continued laboratory evidence of pseudohyperkalemia. Based on the patient’s conscious and interactive condition, ECG findings, and normal plasma potassium level following immediate analysis, the diagnosis of pseudohyperkalemia was made. Laboratory findings of pseudohyperkalemia persisted throughout the period of leukocytosis.

Conclusion:

This case describes pseudohyperkalemia attributed to malignant leucocytosis in a patient with chronic lymphoblastic leukemia (CLL). Practitioners should consider pseudohyperkalemia as the underlying cause of elevated potassium levels in patients with malignant leucocytosis who do not have signs or symptoms of systemic hyperkalemia.