Seeing Red: Blood Sample Hemolysis Is Associated with Prolonged Emergency Department Throughput

Potential medical impact of unrecognized in vitro hypokalemia due to hemolysis: a case series

OBJECTIVES

The destruction of red cells during blood collection or with the processing of the sample continues to occur at a high rate, especially among emergency department (ED) patients. This can produce pre-analytical laboratory errors, particularly for potassium. We determined the incidence of hemolyzed samples and discuss the potential medical impact for hypokalemic patients who potassium level is artificially normal (pseudoeukalemia).

METHODS

Potassium results were obtained for a 6-month period. Using a measured hemolysis index (HI), hemolysis was present in 3.1 % for all potassium ordered (n=94,783) and 7.5 % for ED orders (n=22,770). Most of these samples were reported as having high normal result or were hyperkalemic. There were 22 hemolytic samples with a potassium of <3.5 mmol/L, and 57 hemolytic samples with a potassium in lower limit of normal (3.5-3.8 mmol/L). From this group, we examined the medical histories of 8 selected patients whose initially normal potassium levels were subsequently confirmed to have a potassium values that were below, at, or just above the lower limit of normal due to hemolysis.

RESULTS

The primary complaint for these patients were: necrotizing soft tissue infection, pancreatitis, volume overload from heart failure with reduced ejection fraction, hypertension treated with hydrochlorothiazide, and presence of a short bowel syndrome. A subsequent non-hemolyzed sample was collected demonstrating hypokalemia in all of these patients. Within these cases, there was a potential for harm had hemolysis detection not been performed.

CONCLUSIONS

We demonstrate the medical importance of detecting hemolysis for patients who have pseudoeukalemia. This is relevant because the HI cannot be obtained when electrolytes are tested using whole blood samples, and a normal potassium may lead to inappropriate patient management.

Pediatric hemolysis in emergency departments: Prevalence, risk factors, and clinical implications

OBJECTIVE

This study aimed to analyze the prevalence, risk factors, and clinical implications of hemolyzed laboratory samples in the pediatric emergency department (ED), a subject on which existing data remains scarce.

METHODS

We conducted a multi-site observational cohort analysis of pediatric ED encounters in Metro Detroit, Michigan, United States. The study included participants below 18 years of age who had undergone peripheral intravenous catheter (PIVC) placement and laboratory testing. The primary outcome was the presence of hemolysis, and secondary outcomes included identifying risk factors for hemolysis and assessing the impact of hemolysis on PIVC failure.

RESULTS

Between January 2021 and May 2022, 10,462 ED encounters met inclusion criteria, of which 14.0% showed laboratory evidence of hemolysis. The highest proportion of hemolysis occurred in the infant (age 0-1) population (20.1%). Multivariable regression analysis indicated higher odds of hemolysis for PIVCs placed in the hand/wrist in the toddler (age 2-5) and child (age 6-11) subgroups. PIVCs placed in the hand/wrist also demonstrated higher odds of failure in infants.

CONCLUSIONS

Hemolysis in the pediatric ED population is a frequent complication that occurs at similar rates as in adults. PIVCs placed in the hand/wrist were associated with higher odds of hemolysis compared to those placed in the antecubital fossa. Clinicians should consider alternative locations for PIVC placement if clinically appropriate. Further research is needed to better understand the clinical implications of pediatric hemolysis.

Rapid serum tubes reduce transport hemolysis and false positive rates for high-sensitivity troponin T

INTRODUCTION

Hemolysis in the emergency department (ED) can significantly delay results and appropriate action. We evaluated the main sources of hemolysis during sample collection, and to evaluate the use of rapid serum tubes (RST) as a transport hemolysis-mitigating measure for high-sensitivity troponin T (hs-cTnT) testing.

METHODS

We examined the effect of tube type, tube fill, types of sample draw and collection methods on hemolysis and hs-cTnT in samples (n = 158) from ED patients. We also compared hs-cTnT values in paired RST and plasma separate tube (PST) samples that were hemolysis-free.

RESULTS

The primary source of hemolysis in samples collected in the ED was underfilling tubes. In both tube types, PST and RST, filled tubes showed a median reduction in hemolysis of 69.1 % (p < 0.0001). Blood collected in RST also experienced less hemolysis compared to PST. In hemolysis-free samples, false positive results in PST were noted in patients with hs-cTnT values < 50 ng/l.

CONCLUSION

We suggest that proper tube filling during sample collection and use of RST tubes can significantly reduce the effects of hemolysis. In addition, laboratories should be aware that PST tubes have a non-trivial rate of false positives when hs-cTnT < 50 ng/l.

Hemolyzed Laboratory Specimens in the Emergency Department: An Underappreciated, but Frequent Problem

INTRODUCTION

Hemolysis of blood samples from emergency department (ED) patients leads to delays in treatment and disposition. The aim of this study is to determine the frequency of hemolysis and variables predictive of hemolysis.

METHODS

This observational cohort study was conducted among three institutions: academic tertiary care center and two suburban community EDs, with an annual census of over 270,000 ED visits. Data were obtained from the electronic health record. Adults requiring laboratory analysis with at least one peripheral intravenous catheter (PIVC) inserted within the ED were eligible. Primary outcome was hemolysis of lab samples and secondary outcomes included variables related to PIVC failure.

RESULTS

Between January 8, 2021 and May 9, 2022, 141,609 patient encounters met inclusion criteria. The average age was 55.5 and 57.5% of patients were female. Hemolysis occurred in 24,359 (17.2%) samples. In a multivariate analysis, when compared to 20-gauge catheters, smaller 22-gauge catheters had an increased odds of hemolysis (OR 1.78, 95% confidence interval (CI) 1.65-1.91; P < .001), while larger 18-gauge catheters had a lower odds of hemolysis (OR 0.94; 95% CI 0.90-0.98; P = .0046). Additionally, when compared to antecubital placement, hand/wrist placement demonstrated increased odds of hemolysis (OR 2.06; 95% CI 1.97-2.15; P < .001). Finally, hemolysis was associated with a higher rate of PIVC failure (OR 1.06; 95%CI 1.00-1.13; P = 0.043).

DISCUSSION

This large observational analysis demonstrates that lab hemolysis of is a frequent occurrence among ED patients. Given the added risk of hemolysis with certain placement variables, clinicians should consider catheter gauge/placement location to avoid hemolysis that may result in patient care delays and prolonged hospital stays.

Reducing blood sample hemolysis in the emergency department using S-Monovette® in aspiration mode

Background

Blood sample hemolysis continues to be a significant problem in clinical practice. In vitro hemolysis rates up to 77% have been reported in literature. The use of manual aspiration techniques for blood sampling has previously been shown to reduce the burden of erythrocyte injury in the pre-analytical phase compared to the vacuum collection technique. This study compares the hemolysis rates between two blood sampling methods: 5.0 ml BD Vacutainer® SST™ (BDV) and 4.9 ml S-Monovette® serum gel tubes in aspiration mode (SMA).

Methods

This was a prospective randomised controlled study conducted in an Emergency department (ED). A convenience sample of 191 adult patients, aged 18-90 years old, presenting at the ED and requiring blood samples for serum electrolyte was included in the study. Paired blood samples were obtained through an intravenous cannula from each patient with randomised order of blood draw using SMA or BDV. Patient data was obtained and hemolysis index (HI), serum lactate dehydrogenase (LDH), and serum potassium (K) levels measured.

Results

The adjusted mean HI (35.2 vs 21.5 mg/dL, p < 0.001), serum K (4.38 vs 4.16 mmol/L, p < 0.001) and LDH levels (259.6 vs 228.4 U/L, p < 0.001) were significantly higher in blood samples taken using BDV compared to SMA. The frequency of severely hemolyzed (>150 mg/dL) samples was also higher in blood collected using BDV (16.2%) compared to SMA (0%).

Conclusions

The burden of hemolysis in blood samples taken from IV cannulae can be effectively reduced with the use of manual aspiration using the S-Monovette® blood collection system as compared to BD-Vacutainer.

Hemolysis Control in the Emergency Department by Interventional Blood Sampling

The hemolysis rate in the emergency department (ED) is higher compared to that in other departments. We propose a new blood sampling technique without repeated venipuncture to reduce hemolysis and compare the hemolysis rate between blood collected by this method and that collected with an intravenous (IV) catheter. This prospective study included a nonconsecutive sample of patients visiting the ED (aged ≥ 18 years) of a tertiary urban university hospital. The intravenous catheterization was performed by three pre-trained nurses. The new blood collection technique involved sample collection without removing the catheter needle, performed immediately before the conventional method (through an IV catheter), without additional venipuncture. Two blood samples were collected from each patient using both the new and conventional methods, and the hemolysis index was evaluated. We compared the hemolysis rate between the two methods. From the 260 patients enrolled in this study, 147 (56.5%) were male, and the mean age was 58.3 years. The hemolysis rate of the new blood collection method was 1.9% (5/260), which was significantly lower than that of the conventional method (7.3%; 19/260) (p = 0.001). The new blood collection method can reduce the hemolysis rate as compared to the conventional blood collection method.

Drugs and Conditions That May Mimic Hemolysis

OBJECTIVES

Visual inspection of posttransfusion plasma for hemolysis is a key laboratory method in the investigation of possible acute hemolytic transfusion reactions (AHTRs). Many substances and physiologic conditions can mimic hemolysis in vitro. Isolated reports describe specific cases of interference, but a comprehensive listing is lacking.

METHODS

Using an illustrative case, we summarize available literature on substances and conditions that may mimic hemolysis in vitro. We further describe other substances and conditions that may discolor plasma but are unlikely to be mistaken for hemolysis on visual inspection.

RESULTS

At least 11 substances and conditions have been reported to discolor plasma, in colors ranging from orange to red to brown, including relatively common therapies (eg, eltrombopag, hydroxocobalamin, iron dextran). Other substances are unlikely to be encountered in everyday practice but may mimic hemolysis in particular patient populations. Additional substances may cause plasma discoloration, ranging from blue to green to white, and are associated with a wide variety of therapies and conditions.

CONCLUSIONS

An awareness of the possible preanalytic confounding factors that may mimic hemolysis can aid in the workup of a suspected AHTR. Review of the medical record, use of ancillary testing, and consideration for nonimmune causes of hemolysis can aid in ruling out AHTR.

A Single-Center Prospective Study of the Effects of Different Methods of Phlebotomy in the Emergency Department on Blood Sample Hemolysis Rates

INTRODUCTION

Hemolysis is more commonly seen in the emergency department and causes delays in diagnosis, hospitalization, discharge, and treatment of patients. The aim of this study was to determine the most appropriate phlebotomy method and device to reduce blood sample hemolysis in the emergency department.

METHODS

This prospective, comparative descriptive study involved patients who presented to the emergency department with any medical condition and required blood sampling. Patients were divided into 6 groups according to the method of phlebotomy and the device used for phlebotomy. Data were analyzed with logistic regression.

RESULTS

A total of 715 patients participated in the study. The blood sample hemolysis rate in the emergency department was 25.7%. When the hemolysis rates were compared with a steel straight needle or intravenous catheter, it was found that the use of steel straight needle significantly reduced hemolysis. Blood drawing through a 20 G intravenous catheter with Luer-Lock access device reduces the risk of hemolysis. Male sex and difficult blood collection also have been shown to increase the risk of hemolysis.

DISCUSSION

Blood should be drawn with a steel straight needle instead of an intravenous catheter. However, when that is not possible, we recommend the use of a 20 G intravenous catheter with Luer-Lock access device if a blood sample is to be drawn from intravenous line.

Is There a Risk of Misinterpretation of Potassium Concentration from Undetectable Hemolysis Using a POCT Blood Gas Analyzer in the Emergency Department?

Background and Objectives: Hemolysis is reported to be present in up to 10% of blood gas specimens in the central lab; however, few data on the incidence of hemolysis using a point-of-care testing (POCT) blood gas analysis are available in the setting of the emergency department. The aims of this study were: (1) to analyze the prevalence of hemolysis in blood gas samples collected in the ED using a POCT device; and (2) to evaluate the impact of hemolysis on blood sample results and its clinical consequences. Materials and Methods: We collected 525 consecutive POCT arterial blood gas samples using syringes with electrolyte-balanced heparin within 3 different EDs in the metropolitan area of Rome. Immediately after the collection, the blood samples were checked for the presence of hemolysis with a POCT instrument (i.e., HEMCHECK, H-10 ®). The samples were then subsequently processed for blood gasses, and an electrolytes analysis by a second operator blinded for the hemolysis results. A venous blood sample was simultaneously collected, analyzed for it’s potassium value, and used as a reference. Results: Of the samples, 472 were considered for the statistics, while 53 were excluded due to the high percentage of hemolysis due to operator fault in carrying out the measurement. The final mean hemolysis per operator was 12% (±13% SD), and the total final hemolysis was 14.4%.Potassium (K+) was significantly higher in the hemolyzed group compared with the non-hemolyzed sample (4.60 ± 0.11 vs. 3.99 ± 0.03 mEq/L; p < 0.001), and there were differences between arterial potassium versus venous potassium (D(a-v) K+, 0.29 ± 0.06 vs.−0.19 ± 0.02 mEq/L, p < 0.01). A Bland−Altman analysis confirmed that hemolysis significantly overestimated blood potassium level. Conclusion: Almost 12% of POCT blood gas analysis samples performed in the ED could be hemolyzed, and the presence of this hemolysis is not routinely detected. This could cause an error in the interpretation of the results, leading to the consideration of potassium concentrations being below the lower limit within the normal limits and also leading to the diagnosis of false hyperkalemia, which would have potential clinical consequences in therapeutic decision-making in the ED. The routine use of a POCT hemolysis detector could help prevent any misdiagnoses.

The Hidden Cost of Hemolyzed Blood Samples in the Emergency Department

BACKGROUND

On average, patients with hemolyzed potassium samples spend about 1 h longer in the emergency department (ED), regardless of acuity level or disposition. We aimed to quantify the direct expenses associated with poor-quality preanalytic blood samples collected in the ED.

METHODS

We created a simple table with a range of direct expenses (i.e., costs) and rates of hemolyzed sample draws, allowing for identification of potential high-level cost-of-care impact analysis. We included a range of costs informed by review of literature on the topic. Those costs range from $600 to $3000 per bed-hour. This amount was inflation adjusted from 1996 to 2020 (1.68 × [direct cost per visit] × [100 000 visits per year/365 days/24 h]). We provided a range of hemolysis incidence based on previously reported data.

RESULTS

We showed that for an ED with 100 000 annual visits, a 40% draw rate for routine chemistries (including potassium), and a 10% hemolysis incidence, the direct cost impact of hemolysis waste is approximately $4 million/year as a result of the 1 h of added length of stay on average for a patient with a hemolyzed blood sample. This amount represents an annualized estimated cost of caring for a patient in the ED with an avoidable extended length of stay.

CONCLUSIONS

The financial burden of poor-quality blood samples can be estimated using cost per bed-hour and rate of sample failure. Similar methodology may identify additional QC issues with previously invisible financial implications.

Emergency Nurses' Knowledge, Attitudes, and Practices Related to Blood Sample Hemolysis Prevention: An Exploratory Descriptive Study

INTRODUCTION

The aim of the study was to identify emergency nurses' knowledge, attitudes, and practices related to blood sample hemolysis prevention and explore associations between these factors and demographic characteristics. The current state is unknown. Understanding baseline knowledge, attitudes, and practices addresses a gap in the literature.

METHOD

An exploratory, descriptive design with cross-sectional survey methodology employing a study-specific instrument was used.

RESULTS

Request for participation email was sent to a random sample of 5000 Emergency Nurses Association members, and 427 usable surveys were returned (response rate = 8.5%). Mean years in nursing was 13.85 (standard deviation = 10.78), and 226 (52.9%) were certified emergency nurses. Only 85 participants (19.9%) answered all 3 knowledge questions correctly. Answering the 3 knowledge questions correctly was significantly associated with being a certified emergency nurse (χ² = 7.15, P < .01). Participant responses to attitude items about the sequelae of blood sample hemolysis were skewed toward agreement, and most attitude items were associated with whom participants reported as being primarily responsible for phlebotomy. Emergency nurses remain primarily responsible for phlebotomy as well as addressing hemolyzed samples, but few reported that blood sample hemolysis was addressed at a departmental level.

DISCUSSION

Findings suggest that emergency nurses lack some knowledge related to blood sample hemolysis prevention best practices. Attitudes toward phlebotomy practices may be 1 reason practice has not changed. Every effort should be made to prevent hemolyzed blood samples to decrease delays and costs in emergency care.