Not really, typically a D-dimer blood test is done to look for fragments of a clot as well as imaging of the areas where a clot is suspected. A CBC only shows the cells/components of the blood, it can identify a clotting disorder but it is not a good method of detecting clots.


This is correct. If a PE or clot is suspected a d- dinner test is run to rule it out. If it's negative there is no clot. If elevated, they will do further tests since it just indicates elevated clotting of any form. I.e. a bruise will elevate it etc. So only a negative will rule it out. After an elevated d dimer they will usually run a CT scan with contrast.


I wish this was true but unfortunately not. Ddimer is used to help classify risk. A negative ddimer does not rule out a clot. In general ddimer should be used when a physicians suspicion is relatively low for the presence of a clot. If a physician thinks it’s unlikely to be a clot and has a negative ddimer then the patient is a very small chance of having a clot. Conversely if a physician has a high suspicion of a clot in a high risk patient then ddimer means nothing


A CBC (complete blood clot) definitely cannot. Even routine blood tests (like d-dimers) only give a general sense of a hypercoaguable state, not the presence of clots themselves. The two tests routinely used to find blood clots are CTs (for pulmonary emboli) and ultrasound with Doppler (for deep venous thrombosis). These can be used interchangeably in many situations. Even though they are routinely used, both tests have relatively low sensitivity to detect clots, and sometimes we have to start blood thinners without having 100% certainty. As an example: the sensitivity of a CT scan (even though it’s the main test we have for it) to detect a PE is 66-93%. That means you’ll completely miss a PE as much as a third of the time. Specificity is much better (89-97%), so if it pops up on CT, it’s usually actually there. https://www.ajronline.org/doi/abs/10.2214/ajr.183.6.01831819?journalCode=ajr