Can Teardrop Cells Be Normal? Causes and Meaning

Finding a few teardrop-shaped red blood cells on a blood smear is not automatically a sign of disease. Under standardized grading criteria, a count of zero to one teardrop cell per microscope field is classified as normal, meaning isolated teardrops can appear even in healthy individuals.¹ The real question is how many show up and what other abnormalities accompany them. A handful is unremarkable; a field full of them points toward bone marrow trouble, hemolytic anemia, or one of several other conditions worth investigating.

What Teardrop Cells Actually Are

Teardrop cells, known formally as dacrocytes, are red blood cells that have been stretched or pinched into a shape resembling a teardrop or pear, tapered to a point at one end.² Unlike some other misshapen red cells that bounce back to their normal disc shape after the distorting force is removed, teardrop cells are permanently deformed. They keep their elongated shape because the internal skeleton of the cell membrane has been rearranged in a way that locks the new configuration in place.

That permanent deformation happens through a specific mechanism involving a protein called spectrin, which forms the scaffold beneath the red cell membrane. At body temperature, spectrin subunits can break apart and reconnect. When a red cell is stretched for a prolonged period at normal body temperature, those subunits reassemble in the stretched-out arrangement, making the deformation permanent. Experiments have shown that the same stretching force applied at lower temperatures, where spectrin subunits stay locked together, allows the cell to spring back to its original disc shape afterward.³ This is why teardrop cells, once formed, stay teardrop-shaped for the rest of their lifespan in circulation.

How Many Is Too Many

Pathologists and hematologists don’t simply note whether teardrop cells are present or absent. They grade them. A widely used classification system breaks teardrop cell counts per high-power microscope field into four tiers: normal (zero to one cell per field), mild (two to five), moderate (six to fifteen), and severe (more than fifteen).¹ That bottom tier is the key threshold: seeing one teardrop cell as you scan a field under the microscope falls within the expected range and does not, by itself, call for further workup.

In a large study that screened over 35,000 blood smears from patients with chronic diseases, teardrop cells showed up in about 1.4% of all slides. Among those positive smears, the overwhelming majority fell into the mild category. Roughly 86% of patients with detectable teardrop cells had mild dacrocytosis, while 14% had moderate counts. Not a single case of severe dacrocytosis appeared in the entire sample.¹ So even among people who are genuinely ill with various chronic conditions, the teardrop cell burden is usually low.

The Myelofibrosis Connection

When doctors see teardrop cells, the first condition they think of is myelofibrosis, a disorder in which the bone marrow is progressively replaced by fibrous scar tissue. As the marrow becomes stiff and crowded, red blood cells have to squeeze through narrow, abnormal channels to escape into the bloodstream. That mechanical squeezing stretches them, and because it happens at body temperature, the deformation becomes permanent.

Teardrop cells are so characteristic of myelofibrosis that they serve as one of the distinguishing features separating it from other causes of marrow scarring. In a study comparing primary myelofibrosis (the kind that arises from a bone marrow cancer) to secondary myelofibrosis caused by pulmonary hypertension, the presence of teardrop cells in the peripheral blood was one of the hallmarks of the cancerous form. Patients with secondary marrow fibrosis from lung-related causes did not show the same pattern of circulating teardrop cells.⁴ That means teardrop cells are not just a generic marker of fibrosis in the bone marrow; they carry diagnostic weight in distinguishing which type of fibrosis a patient has.

Cancer Spreading to the Bone Marrow

Myelofibrosis is not the only condition that crowds the bone marrow. When cancers from other organs metastasize to the bone, they physically replace the normal marrow tissue and force the body to produce blood cells in abnormal locations like the spleen and liver. This process, called myelophthisic anemia, pushes immature blood cells into the circulation alongside teardrop cells.

A documented case involved a 57-year-old woman whose blood smear showed these hallmarks. She was initially misdiagnosed with a different blood disorder before the true cause was identified as stage four lobular breast carcinoma that had spread to her bone marrow.⁵ Breast tumors have a particular tendency to spread to bone, and when they do, the disruption to normal blood cell production creates the telltale pattern of teardrop cells alongside immature white and red blood cells. Other cancers that metastasize to bone, including prostate, lung, and certain lymphomas, can produce similar blood smear findings.

In the large screening study mentioned earlier, cancer of all types was the single most common diagnosis among patients whose smears showed teardrop cells, accounting for about one in five of all positive cases.¹ That makes teardrop cells clinically important even outside hematology: they can be the first clue that a solid tumor has invaded the marrow.

Hemolytic Anemias Produce Teardrop Cells Too

The classical teaching links teardrop cells almost exclusively to marrow fibrosis, but research has shown they turn up far more broadly than that. In a study examining blood smears from patients with two types of hemolytic anemia, where red blood cells are being destroyed faster than normal, teardrop cells appeared at striking rates. Roughly 89% of patients with autoimmune hemolytic anemia and 91% of patients with microangiopathic hemolytic anemia had detectable teardrop cells. By comparison, only about 19% of control subjects showed any.²

The difference was not subtle. Teardrop cell counts between the hemolytic anemia groups and the control group were statistically far apart. This finding is meaningful because it challenges the reflex of automatically assuming that teardrop cells equal bone marrow fibrosis. In autoimmune hemolytic anemia, the body’s immune system attacks its own red cells. In microangiopathic hemolytic anemia, red cells are shredded by passing through damaged small blood vessels. Neither condition involves marrow fibrosis in the classic sense, yet both generate teardrop cells at very high rates. The physical shearing and fragmentation these cells undergo before they are removed from circulation likely produces the same kind of permanent membrane deformation.

Chronic Diseases You Might Not Expect

The same large study of over 35,000 smears turned up teardrop cells in a diverse set of chronic conditions that go well beyond blood cancers and hemolytic anemias. After cancer, the next most common diagnoses associated with teardrop cells were systemic lupus erythematosus (about 20% of positive cases), liver cirrhosis (about 15%), and diabetes (roughly 8%).¹ The degree of dacrocytosis did not correlate significantly with any particular diagnosis, meaning that having lupus versus cancer versus cirrhosis did not predict whether someone would have more or fewer teardrop cells.

This breadth is important. A patient with cirrhosis whose blood smear shows a few teardrop cells does not necessarily need a bone marrow biopsy for myelofibrosis. The same goes for someone with poorly controlled diabetes or an autoimmune condition. Teardrop cells in these settings are a reflection of chronic systemic stress on the blood and bone marrow, not a specific marker pointing to one disease. Context is everything: the rest of the blood count, the clinical picture, and whether other abnormal cell shapes are present all factor into what teardrop cells mean for a given patient.

One particularly notable finding from that study was that an enlarged spleen was not required for teardrop cells to appear. The traditional teaching held that teardrop cells form when red cells squeeze through an enlarged spleen, and while the spleen does play a role, the data showed that patients without significant splenomegaly still developed teardrop cells. The title of the study itself makes this point: “Splenomegaly is not mandatory for teardrop cells genesis.”¹

The Spleen’s Role and What Happens After Removal

Even though an enlarged spleen is not strictly necessary for teardrop cell formation, the spleen still plays a substantial role, especially in myelofibrosis. Evidence for this comes from studying patients before and after splenectomy. In a study of patients with agnogenic myeloid metaplasia (a form of myelofibrosis), the average count before spleen removal was about 42 teardrop cells per 1,000 red blood cells. After splenectomy, that dropped to about 11 per 1,000, a roughly fourfold decrease. Only one out of thirteen patients failed to show this reduction.⁶

The implication is that in myelofibrosis, the spleen is a major site where red cells get physically reshaped. As the marrow becomes fibrotic and less functional, the spleen takes over more and more blood cell production, and red cells passing through its congested, abnormal tissue are squeezed into teardrop shapes. Remove the spleen and you eliminate that mechanical bottleneck, though not entirely: the post-splenectomy patients still had some teardrop cells, suggesting that other mechanisms and other sites contribute as well.

Thalassemia, Iron Deficiency, and Other Anemias

Beyond the dramatic scenarios of marrow invasion and hemolysis, teardrop cells appear in some surprisingly common anemias. Beta-thalassemia, iron-deficiency anemia, and certain other inherited hemolytic anemias can all produce teardrop cells on a blood smear.⁷ In thalassemia, red cells are already abnormally fragile and prone to deformation because of imbalanced hemoglobin production. In iron deficiency, the cells are thinner and more flexible than normal, which may make them more susceptible to permanent reshaping under physical stress.

These are conditions that affect millions of people worldwide. A person with moderate iron-deficiency anemia or thalassemia trait who gets a blood smear reviewed might see a comment about teardrop cells and panic, thinking it means something serious like cancer or myelofibrosis. In practice, mild teardrop cell counts in these settings are expected and do not carry the same alarm. The quantity matters, and so does what else the smear shows. A blood smear with a few teardrop cells alongside the small, pale red cells typical of iron deficiency tells a very different story than a smear packed with teardrop cells plus immature white cells and large platelets.

Artifacts and Smear Preparation

Not every teardrop-shaped cell on a slide is a true dacrocyte. The physical process of making a blood smear, dragging a drop of blood across a glass slide with another slide, can artificially stretch normal red cells into teardrop-like shapes. These artifacts tend to cluster at the edges and feathered end of the smear, where the spreading force is strongest, and they often all point in the same direction (the direction of the smear). True dacrocytes, by contrast, tend to point in random directions and appear across the slide rather than just at the edges.

Lab technicians are trained to distinguish the two, but automated systems have been increasingly tasked with catching teardrop cells as well. Machine learning models trained on digital microscopy images have shown high accuracy for identifying teardrop cells, with one pilot study reporting a classification accuracy of over 99% and a precision of about 92% for teardrop cell detection.⁸ That study was performed on cattle blood rather than human blood, so the numbers should not be directly transferred to human diagnostics, but the underlying approach of training algorithms to classify abnormal red cell shapes is being actively developed for clinical use. The challenge for automated systems is the same one human observers face: distinguishing true teardrop cells from smear artifacts and from other elongated cell shapes like elliptocytes.

What to Do If Your Report Mentions Teardrop Cells

If you receive a lab report that notes teardrop cells, the first thing worth checking is whether the report comments on how many were seen. A note like “rare dacrocytes” or “occasional teardrop cells” in an otherwise normal blood count is very different from “numerous dacrocytes with leukoerythroblastic picture.” The latter phrase, combining teardrop cells with immature blood cells, is the combination that strongly suggests bone marrow infiltration or fibrosis and typically triggers further investigation like a bone marrow biopsy.

Your doctor will also look at the rest of the complete blood count. Teardrop cells accompanied by anemia, abnormal white cell counts, and enlarged or oddly shaped platelets paint a different picture than teardrop cells sitting in an otherwise unremarkable blood panel. The clinical context matters too: a patient with known beta-thalassemia trait who shows a few teardrop cells needs no additional workup for that finding alone, while a patient with unexplained weight loss, night sweats, and a palpable spleen warrants a closer look regardless of how many teardrop cells are on the smear.

One common source of confusion is that automated blood cell analyzers flag abnormal cell morphology using internal algorithms, and different machines have different sensitivity thresholds. A flag for “poikilocytosis” (meaning abnormally shaped red cells of various types) on an automated report sometimes leads to a manual smear review that reveals a few teardrop cells among other mildly abnormal shapes. In many of these cases, the findings reflect a nonspecific stress on red cell production rather than a single identifiable disease, and the flag does not always lead to a diagnosis.

Why Teardrop Cells Get Overcounted as a Warning Sign

Medical training tends to emphasize the scariest associations of any lab finding, because missing a serious disease is more dangerous than over-investigating. Teardrop cells are taught primarily in the context of myelofibrosis and bone marrow cancers, so both patients and clinicians can overreact to seeing them on a smear. The evidence paints a more nuanced picture: the conditions associated with teardrop cells range from life-threatening bone marrow disorders to benign nutritional anemias, and even healthy controls show teardrop cells at low rates (about 19% of control slides in one study had at least some detectable dacrocytes).²

That 19% figure is worth sitting with. It means roughly one in five apparently healthy people will have at least a detectable teardrop cell on their blood smear if someone looks carefully enough. The cells are not supposed to be there in large numbers, but their mere presence is not pathological. The shift from “normal variant” to “clinically meaningful” depends on quantity, accompanying abnormalities, and clinical symptoms. A blood smear is one data point in a larger diagnostic puzzle, and teardrop cells are one piece of the smear. Treated in isolation, they can mislead in either direction: missed when they matter, or chased when they don’t.