This research study is looking at a small device that measures white blood cell (WBC) counts by being placed against the finger nail for participants who are undergoing stem cell transplantation at Massachusetts General Hospital or have a hematologic malignancy and are being seen as an outpatient.

The objective of this study is to obtain data that would support the use of a method to obtain WBC counts from images of small blood vessels called capillaries. These would be obtained by pressing a small device on the surface of participants' finger nails to look through the nail. These images will be obtained using a portable microscope called the Dino-Lite Digital Microscope.

Having a non-invasive way to quickly measure WBC counts could be useful for a variety of healthcare applications.

Inclusion Criteria:

• Patients with lymphoid malignancies or plasma cell dyscrasias who are admitted to the Massachusetts General Hospital to undergo autologous stem cell transplantation or are seen in the outpatient clinic
• Age ≥ 18 years
• Ability to understand and the willingness to sign a written informed consent document.
• Patients must have WBC ≥ 3000 / µl and ANC ≥ 1500 / µl at admission or their last clinical visit to be enrolled.

Exclusion Criteria:

• History of allergic reactions attributed to compounds of similar chemical or biologic composition of baby oil.
• Myelodysplasia
• Skin phototype < 4 in the Fitzpatrick scale.

No plan to share data